21397056510 has 16 divisors (see below), whose sum is σ = 51352935696. Its totient is φ = 5705881728.

The previous prime is 21397056493. The next prime is 21397056521. The reversal of 21397056510 is 1565079312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 356617579 + ... + 356617638.

It is an arithmetic number, because the mean of its divisors is an integer number (3209558481).

Almost surely, 2^21397056510 is an apocalyptic number.

21397056510 is an abundant number, since it is smaller than the sum of its proper divisors (29955879186).

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

21397056510 is a wasteful number, since it uses less digits than its factorization.

21397056510 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 713235227.

The product of its (nonzero) digits is 56700, while the sum is 39.

It can be divided in two parts, 213970 and 56510, that added together give a triangular number (270480 = T₇₃₅).

The spelling of 21397056510 in words is "twenty-one billion, three hundred ninety-seven million, fifty-six thousand, five hundred ten".