1218620231 has 12 divisors (see below), whose sum is σ = 1299523632. Its totient is φ = 1142504448.

The previous prime is 1218620213. The next prime is 1218620251. The reversal of 1218620231 is 1320268121.

It is a de Polignac number, because none of the positive numbers 2^k-1218620231 is a prime.

It is a super-2 number, since 2×1218620231² = 2970070534804986722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1218620231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1218620251) 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, 67991 + ... + 84023.

It is an arithmetic number, because the mean of its divisors is an integer number (108293636).

Almost surely, 2^1218620231 is an apocalyptic number.

1218620231 is a deficient number, since it is larger than the sum of its proper divisors (80903401).

1218620231 is a wasteful number, since it uses less digits than its factorization.

1218620231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16330 (or 16313 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 1218620231 is about 34908.7414697236. The cubic root of 1218620231 is about 1068.1267573766.

Adding to 1218620231 its reverse (1320268121), we get a palindrome (2538888352).

The spelling of 1218620231 in words is "one billion, two hundred eighteen million, six hundred twenty thousand, two hundred thirty-one".