1218747155 has 4 divisors (see below), whose sum is σ = 1462496592. Its totient is φ = 974997720.

The previous prime is 1218747073. The next prime is 1218747157. The reversal of 1218747155 is 5517478121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5517478121 = 61 ⋅90450461.

It is not a de Polignac number, because 1218747155 - 2²² = 1214552851 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1218747157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121874711 + ... + 121874720.

It is an arithmetic number, because the mean of its divisors is an integer number (365624148).

Almost surely, 2^1218747155 is an apocalyptic number.

1218747155 is a deficient number, since it is larger than the sum of its proper divisors (243749437).

1218747155 is an equidigital number, since it uses as much as digits as its factorization.

1218747155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243749436.

The product of its digits is 78400, while the sum is 41.

The square root of 1218747155 is about 34910.5593624622. The cubic root of 1218747155 is about 1068.1638392639.

The spelling of 1218747155 in words is "one billion, two hundred eighteen million, seven hundred forty-seven thousand, one hundred fifty-five".