21892697521 has 2 divisors, whose sum is σ = 21892697522. Its totient is φ = 21892697520.

The previous prime is 21892697509. The next prime is 21892697549. The reversal of 21892697521 is 12579629812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15119407521 + 6773290000 = 122961^2 + 82300^2 .

It is a cyclic number.

It is not a de Polignac number, because 21892697521 - 2³³ = 13302762929 is a prime.

It is not a weakly prime, because it can be changed into another prime (21892697221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10946348760 + 10946348761.

It is an arithmetic number, because the mean of its divisors is an integer number (10946348761).

Almost surely, 2^21892697521 is an apocalyptic number.

It is an amenable number.

21892697521 is a deficient number, since it is larger than the sum of its proper divisors (1).

21892697521 is an equidigital number, since it uses as much as digits as its factorization.

21892697521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1088640, while the sum is 52.

The spelling of 21892697521 in words is "twenty-one billion, eight hundred ninety-two million, six hundred ninety-seven thousand, five hundred twenty-one".