218428488631 has 4 divisors (see below), whose sum is σ = 218454615432. Its totient is φ = 218402361832.

The previous prime is 218428488623. The next prime is 218428488643. The reversal of 218428488631 is 136884824812.

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

It is a cyclic number.

It is not a de Polignac number, because 218428488631 - 2³ = 218428488623 is a prime.

It is a super-2 number, since 2×218428488631² (a number of 23 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 (218428488601) 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, 13050856 + ... + 13067581.

It is an arithmetic number, because the mean of its divisors is an integer number (54613653858).

Almost surely, 2^218428488631 is an apocalyptic number.

218428488631 is a deficient number, since it is larger than the sum of its proper divisors (26126801).

218428488631 is an equidigital number, since it uses as much as digits as its factorization.

218428488631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26126800.

The product of its digits is 4718592, while the sum is 55.

The spelling of 218428488631 in words is "two hundred eighteen billion, four hundred twenty-eight million, four hundred eighty-eight thousand, six hundred thirty-one".