21540235240520 has 64 divisors (see below), whose sum is σ = 49382669952000. Its totient is φ = 8453064625408.

The previous prime is 21540235240507. The next prime is 21540235240541. The reversal of 21540235240520 is 2504253204512.

It is a happy 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, 39925121 + ... + 40461039.

It is an arithmetic number, because the mean of its divisors is an integer number (771604218000).

Almost surely, 2^{21540235240520} is an apocalyptic number.

21540235240520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21540235240520 is an abundant number, since it is smaller than the sum of its proper divisors (27842434711480).

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

21540235240520 is a wasteful number, since it uses less digits than its factorization.

21540235240520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554942 (or 554938 counting only the distinct ones).

The product of its (nonzero) digits is 96000, while the sum is 35.

The spelling of 21540235240520 in words is "twenty-one trillion, five hundred forty billion, two hundred thirty-five million, two hundred forty thousand, five hundred twenty".