81590769 has 72 divisors (see below), whose sum is σ = 143037440. Its totient is φ = 44416512.

The previous prime is 81590711. The next prime is 81590777. The reversal of 81590769 is 96709518.

It is not a de Polignac number, because 81590769 - 2¹¹ = 81588721 is a prime.

It is a super-2 number, since 2×81590769² = 13314107172022722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81595769) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 642384 + ... + 642510.

Almost surely, 2^81590769 is an apocalyptic number.

It is an amenable number.

81590769 is a deficient number, since it is larger than the sum of its proper divisors (61446671).

81590769 is a wasteful number, since it uses less digits than its factorization.

81590769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199 (or 179 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 45.

The square root of 81590769 is about 9032.7608736200. The cubic root of 81590769 is about 433.7242207990.

The spelling of 81590769 in words is "eighty-one million, five hundred ninety thousand, seven hundred sixty-nine".