21021977725492 has 12 divisors (see below), whose sum is σ = 36795608609760. Its totient is φ = 10508946694136.

The previous prime is 21021977725481. The next prime is 21021977725523. The reversal of 21021977725492 is 29452777912012.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 510518992 + ... + 510560167.

It is an arithmetic number, because the mean of its divisors is an integer number (3066300717480).

Almost surely, 2^{21021977725492} is an apocalyptic number.

It is an amenable number.

21021977725492 is a deficient number, since it is larger than the sum of its proper divisors (15773630884268).

21021977725492 is a wasteful number, since it uses less digits than its factorization.

21021977725492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1021084310 (or 1021084308 counting only the distinct ones).

The product of its (nonzero) digits is 8890560, while the sum is 58.

The spelling of 21021977725492 in words is "twenty-one trillion, twenty-one billion, nine hundred seventy-seven million, seven hundred twenty-five thousand, four hundred ninety-two".