18955055981 has 12 divisors (see below), whose sum is σ = 20259229632. Its totient is φ = 17730560448.

The previous prime is 18955055971. The next prime is 18955055983.

It is a happy number.

18955055981 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 18955055981 - 2³⁴ = 1775186797 is a prime.

It is a super-2 number, since 2×18955055981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18955055983) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 154085 + ... + 248298.

It is an arithmetic number, because the mean of its divisors is an integer number (1688269136).

Almost surely, 2^18955055981 is an apocalyptic number.

It is an amenable number.

18955055981 is a deficient number, since it is larger than the sum of its proper divisors (1304173651).

18955055981 is a wasteful number, since it uses less digits than its factorization.

18955055981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 402580 (or 402563 counting only the distinct ones).

The product of its (nonzero) digits is 3240000, while the sum is 56.

Subtracting from 18955055981 its product of nonzero digits (3240000), we obtain a palindrome (18951815981).

The spelling of 18955055981 in words is "eighteen billion, nine hundred fifty-five million, fifty-five thousand, nine hundred eighty-one".