921582720081 has 27 divisors (see below), whose sum is σ = 1350487696233. Its totient is φ = 605600722440.

The previous prime is 921582720073. The next prime is 921582720103. The reversal of 921582720081 is 180027285129.

The square root of 921582720081 is 959991.

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

It is not a de Polignac number, because 921582720081 - 2³ = 921582720073 is a prime.

It is a super-2 number, since 2×921582720081² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (921582720061) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 204475830 + ... + 204480336.

Almost surely, 2^921582720081 is an apocalyptic number.

921582720081 is the 959991-st square number.

921582720081 is the 479996-th centered octagonal number.

It is an amenable number.

921582720081 is a deficient number, since it is larger than the sum of its proper divisors (428904976152).

921582720081 is an frugal number, since it uses more digits than its factorization.

921582720081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9162 (or 4581 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The spelling of 921582720081 in words is "nine hundred twenty-one billion, five hundred eighty-two million, seven hundred twenty thousand, eighty-one".