21023604520 has 128 divisors (see below), whose sum is σ = 50376816000. Its totient is φ = 7883545600.

The previous prime is 21023604509. The next prime is 21023604529. The reversal of 21023604520 is 2540632012.

It is not an unprimeable number, because it can be changed into a prime (21023604529) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5678670 + ... + 5682370.

It is an arithmetic number, because the mean of its divisors is an integer number (393568875).

Almost surely, 2^21023604520 is an apocalyptic number.

21023604520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21023604520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25188408000).

21023604520 is an abundant number, since it is smaller than the sum of its proper divisors (29353211480).

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

21023604520 is a wasteful number, since it uses less digits than its factorization.

21023604520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3883 (or 3879 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

The spelling of 21023604520 in words is "twenty-one billion, twenty-three million, six hundred four thousand, five hundred twenty".