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21213012 = 2231767751
BaseRepresentation
bin101000011101…
…0111101010100
31110220201210010
41100322331110
520412304022
62034400220
7345210342
oct120727524
943821703
1021213012
1110a79717
127130070
1345195a2
142b62992
151ce050c
hex143af54

21213012 has 12 divisors (see below), whose sum is σ = 49497056. Its totient is φ = 7071000.

The previous prime is 21213011. The next prime is 21213013. The reversal of 21213012 is 21031212.

It is an interprime number because it is at equal distance from previous prime (21213011) and next prime (21213013).

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×212130122 = 899983756224288, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12), and also a Moran number because the ratio is a prime number: 1767751 = 21213012 / (2 + 1 + 2 + 1 + 3 + 0 + 1 + 2).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 883864 + ... + 883887.

Almost surely, 221213012 is an apocalyptic number.

It is an amenable number.

21213012 is an abundant number, since it is smaller than the sum of its proper divisors (28284044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21213012 is a wasteful number, since it uses less digits than its factorization.

21213012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1767758 (or 1767756 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21213012 is about 4605.7585694433. The cubic root of 21213012 is about 276.8221129326.

Adding to 21213012 its reverse (21031212), we get a palindrome (42244224).

The spelling of 21213012 in words is "twenty-one million, two hundred thirteen thousand, twelve".

Divisors: 1 2 3 4 6 12 1767751 3535502 5303253 7071004 10606506 21213012