21300020 has 48 divisors (see below), whose sum is σ = 51383808. Its totient is φ = 7265280.

The previous prime is 21299987. The next prime is 21300029. The reversal of 21300020 is 2000312.

It is a junction number, because it is equal to n+sod(n) for n = 21299980 and 21300007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21300029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49205 + ... + 49635.

It is an arithmetic number, because the mean of its divisors is an integer number (1070496).

Almost surely, 2^21300020 is an apocalyptic number.

21300020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21300020 is an abundant number, since it is smaller than the sum of its proper divisors (30083788).

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

21300020 is a wasteful number, since it uses less digits than its factorization.

21300020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 800 (or 798 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 8.

The square root of 21300020 is about 4615.1944704422. The cubic root of 21300020 is about 277.2000709354.

Adding to 21300020 its reverse (2000312), we get a palindrome (23300332).

The spelling of 21300020 in words is "twenty-one million, three hundred thousand, twenty".