18988564401 has 45 divisors (see below), whose sum is σ = 28953617979. Its totient is φ = 12401910000.

The previous prime is 18988564393. The next prime is 18988564421. The reversal of 18988564401 is 10446588981.

It is a happy number.

The square root of 18988564401 is 137799.

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

18988564401 is a `hidden beast` number, since 18 + 98 + 85 + 64 + 401 = 666.

It can be written as a sum of positive squares in only one way, i.e., 617472801 + 18371091600 = 24849^2 + 135540^2 .

It is not a de Polignac number, because 18988564401 - 2³ = 18988564393 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18988564421) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 75651526 + ... + 75651776.

Almost surely, 2^18988564401 is an apocalyptic number.

18988564401 is the 137799-th square number.

18988564401 is the 68900-th centered octagonal number.

It is an amenable number.

18988564401 is a deficient number, since it is larger than the sum of its proper divisors (9965053578).

18988564401 is an frugal number, since it uses more digits than its factorization.

18988564401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 636 (or 315 counting only the distinct ones).

The product of its (nonzero) digits is 2211840, while the sum is 54.

The spelling of 18988564401 in words is "eighteen billion, nine hundred eighty-eight million, five hundred sixty-four thousand, four hundred one".