81574263769 has 4 divisors (see below), whose sum is σ = 82322651620. Its totient is φ = 80825875920.

The previous prime is 81574263761. The next prime is 81574263781. The reversal of 81574263769 is 96736247518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96736247518 = 2 ⋅48368123759.

It can be written as a sum of positive squares in 2 ways, for example, as 22496100169 + 59078163600 = 149987^2 + 243060^2 .

It is a cyclic number.

It is not a de Polignac number, because 81574263769 - 2³ = 81574263761 is a prime.

It is a super-2 number, since 2×81574263769² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81574263761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 374193762 + ... + 374193979.

It is an arithmetic number, because the mean of its divisors is an integer number (20580662905).

Almost surely, 2^81574263769 is an apocalyptic number.

It is an amenable number.

81574263769 is a deficient number, since it is larger than the sum of its proper divisors (748387851).

81574263769 is a wasteful number, since it uses less digits than its factorization.

81574263769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 748387850.

The product of its digits is 15240960, while the sum is 58.

The spelling of 81574263769 in words is "eighty-one billion, five hundred seventy-four million, two hundred sixty-three thousand, seven hundred sixty-nine".