38720801556581 has 4 divisors (see below), whose sum is σ = 39155866742700. Its totient is φ = 38285736370464.

The previous prime is 38720801556559. The next prime is 38720801556601. The reversal of 38720801556581 is 18565510802783.

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 6939057055681 + 31781744500900 = 2634209^2 + 5637530^2 .

It is a cyclic number.

It is not a de Polignac number, because 38720801556581 - 2¹⁸ = 38720801294437 is a prime.

It is a super-2 number, since 2×38720801556581² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 38720801556581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (38720801556181) 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, 217532592926 + ... + 217532593103.

It is an arithmetic number, because the mean of its divisors is an integer number (9788966685675).

Almost surely, 2^{38720801556581} is an apocalyptic number.

It is an amenable number.

38720801556581 is a deficient number, since it is larger than the sum of its proper divisors (435065186119).

38720801556581 is an equidigital number, since it uses as much as digits as its factorization.

38720801556581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 435065186118.

The product of its (nonzero) digits is 16128000, while the sum is 59.

The spelling of 38720801556581 in words is "thirty-eight trillion, seven hundred twenty billion, eight hundred one million, five hundred fifty-six thousand, five hundred eighty-one".