38656811581 has 4 divisors (see below), whose sum is σ = 40930741692. Its totient is φ = 36382881472.

The previous prime is 38656811563. The next prime is 38656811621. The reversal of 38656811581 is 18511865683.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 29381388100 + 9275423481 = 171410^2 + 96309^2 .

It is a cyclic number.

It is not a de Polignac number, because 38656811581 - 2⁵ = 38656811549 is a prime.

It is a super-2 number, since 2×38656811581² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (38656811521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1136965030 + ... + 1136965063.

It is an arithmetic number, because the mean of its divisors is an integer number (10232685423).

Almost surely, 2^38656811581 is an apocalyptic number.

It is an amenable number.

38656811581 is a deficient number, since it is larger than the sum of its proper divisors (2273930111).

38656811581 is a wasteful number, since it uses less digits than its factorization.

38656811581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2273930110.

The product of its digits is 1382400, while the sum is 52.

The spelling of 38656811581 in words is "thirty-eight billion, six hundred fifty-six million, eight hundred eleven thousand, five hundred eighty-one".