21021012120 has 64 divisors (see below), whose sum is σ = 63213696000. Its totient is φ = 5592211328.

The previous prime is 21021012109. The next prime is 21021012139. The reversal of 21021012120 is 2121012012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21021012096 and 21021012105.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 158760 + ... + 259319.

It is an arithmetic number, because the mean of its divisors is an integer number (987714000).

Almost surely, 2^21021012120 is an apocalyptic number.

21021012120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021012120 is an abundant number, since it is smaller than the sum of its proper divisors (42192683880).

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

21021012120 is a wasteful number, since it uses less digits than its factorization.

21021012120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 418512 (or 418508 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21021012120 its reverse (2121012012), we get a palindrome (23142024132).

The spelling of 21021012120 in words is "twenty-one billion, twenty-one million, twelve thousand, one hundred twenty".