1218493931 has 4 divisors (see below), whose sum is σ = 1271471952. Its totient is φ = 1165515912.

The previous prime is 1218493919. The next prime is 1218493937. The reversal of 1218493931 is 1393948121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1393948121 = 11197 ⋅124493.

It is a cyclic number.

It is not a de Polignac number, because 1218493931 - 2²² = 1214299627 is a prime.

It is a super-2 number, since 2×1218493931² = 2969454919767665522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1218493937) 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, 26488976 + ... + 26489021.

It is an arithmetic number, because the mean of its divisors is an integer number (317867988).

Almost surely, 2^1218493931 is an apocalyptic number.

1218493931 is a deficient number, since it is larger than the sum of its proper divisors (52978021).

1218493931 is an equidigital number, since it uses as much as digits as its factorization.

1218493931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52978020.

The product of its digits is 46656, while the sum is 41.

The square root of 1218493931 is about 34906.9324203660. The cubic root of 1218493931 is about 1068.0898552401.

The spelling of 1218493931 in words is "one billion, two hundred eighteen million, four hundred ninety-three thousand, nine hundred thirty-one".