21145230520 has 64 divisors (see below), whose sum is σ = 49242816000. Its totient is φ = 8162208768.

The previous prime is 21145230493. The next prime is 21145230523. The reversal of 21145230520 is 2503254112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21145230523) 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, 3143721 + ... + 3150439.

It is an arithmetic number, because the mean of its divisors is an integer number (769419000).

Almost surely, 2^21145230520 is an apocalyptic number.

21145230520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21145230520 is an abundant number, since it is smaller than the sum of its proper divisors (28097585480).

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

21145230520 is a wasteful number, since it uses less digits than its factorization.

21145230520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9472 (or 9468 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

Adding to 21145230520 its reverse (2503254112), we get a palindrome (23648484632).

The spelling of 21145230520 in words is "twenty-one billion, one hundred forty-five million, two hundred thirty thousand, five hundred twenty".