1218831959 has 2 divisors, whose sum is σ = 1218831960. Its totient is φ = 1218831958.

The previous prime is 1218831877. The next prime is 1218831973. The reversal of 1218831959 is 9591388121.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1218831959 - 2²⁴ = 1202054743 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1218831979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609415979 + 609415980.

It is an arithmetic number, because the mean of its divisors is an integer number (609415980).

Almost surely, 2^1218831959 is an apocalyptic number.

1218831959 is a deficient number, since it is larger than the sum of its proper divisors (1).

1218831959 is an equidigital number, since it uses as much as digits as its factorization.

1218831959 is an evil number, because the sum of its binary digits is even.

The product of its digits is 155520, while the sum is 47.

The square root of 1218831959 is about 34911.7739308675. The cubic root of 1218831959 is about 1068.1886140131.

The spelling of 1218831959 in words is "one billion, two hundred eighteen million, eight hundred thirty-one thousand, nine hundred fifty-nine".