21201012 has 36 divisors (see below), whose sum is σ = 61248096. Its totient is φ = 6057360.

The previous prime is 21200987. The next prime is 21201031. The reversal of 21201012 is 21010212.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21200985 and 21201003.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 41814 + ... + 42317.

It is an arithmetic number, because the mean of its divisors is an integer number (1701336).

Almost surely, 2^21201012 is an apocalyptic number.

It is an amenable number.

21201012 is an abundant number, since it is smaller than the sum of its proper divisors (40047084).

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

21201012 is a wasteful number, since it uses less digits than its factorization.

21201012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84148 (or 84143 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21201012 is about 4604.4556681545. The cubic root of 21201012 is about 276.7699045375.

Adding to 21201012 its reverse (21010212), we get a palindrome (42211224).

The spelling of 21201012 in words is "twenty-one million, two hundred one thousand, twelve".