18557924867881 has 9 divisors (see below), whose sum is σ = 21587825231031. Its totient is φ = 15906766896552.

The previous prime is 18557924867843. The next prime is 18557924867957. The reversal of 18557924867881 is 18876842975581.

The square root of 18557924867881 is 4307891.

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

It can be written as a sum of positive squares in only one way, i.e., 586396035225 + 17971528832656 = 765765^2 + 4239284^2 .

It is not a de Polignac number, because 18557924867881 - 2⁷ = 18557924867753 is a prime.

It is a super-2 number, since 2×18557924867881² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18557924867081) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 29847531 + ... + 30462943.

Almost surely, 2^{18557924867881} is an apocalyptic number.

18557924867881 is the 4307891-st square number.

18557924867881 is the 2153946-th centered octagonal number.

It is an amenable number.

18557924867881 is a deficient number, since it is larger than the sum of its proper divisors (3029900363150).

18557924867881 is an frugal number, since it uses more digits than its factorization.

18557924867881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1230840 (or 615420 counting only the distinct ones).

The product of its digits is 2167603200, while the sum is 79.

The spelling of 18557924867881 in words is "eighteen trillion, five hundred fifty-seven billion, nine hundred twenty-four million, eight hundred sixty-seven thousand, eight hundred eighty-one".