21432909125761 has 45 divisors (see below), whose sum is σ = 25268051132961. Its totient is φ = 18178761927816.

The previous prime is 21432909125759. The next prime is 21432909125833. The reversal of 21432909125761 is 16752190923412.

The square root of 21432909125761 is 4629569.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 21432909125761 - 2¹ = 21432909125759 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21432909125699 and 21432909125708.

It is not an unprimeable number, because it can be changed into a prime (21432909125731) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 24272829826 + ... + 24272830708.

Almost surely, 2^{21432909125761} is an apocalyptic number.

21432909125761 is the 4629569-th square number.

21432909125761 is the 2314785-th centered octagonal number.

It is an amenable number.

21432909125761 is a deficient number, since it is larger than the sum of its proper divisors (3835142007200).

21432909125761 is an frugal number, since it uses more digits than its factorization.

21432909125761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2008 (or 997 counting only the distinct ones).

The product of its (nonzero) digits is 1632960, while the sum is 52.

The spelling of 21432909125761 in words is "twenty-one trillion, four hundred thirty-two billion, nine hundred nine million, one hundred twenty-five thousand, seven hundred sixty-one".