1218442665 has 16 divisors (see below), whose sum is σ = 2126736576. Its totient is φ = 590760000.

The previous prime is 1218442661. The next prime is 1218442679. The reversal of 1218442665 is 5662448121.

It is a happy number.

It is not a de Polignac number, because 1218442665 - 2² = 1218442661 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1218442661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3692086 + ... + 3692415.

It is an arithmetic number, because the mean of its divisors is an integer number (132921036).

Almost surely, 2^1218442665 is an apocalyptic number.

1218442665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1218442665 is a deficient number, since it is larger than the sum of its proper divisors (908293911).

1218442665 is a wasteful number, since it uses less digits than its factorization.

1218442665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7384520.

The product of its digits is 92160, while the sum is 39.

The square root of 1218442665 is about 34906.1980885917. The cubic root of 1218442665 is about 1068.0748756928.

The spelling of 1218442665 in words is "one billion, two hundred eighteen million, four hundred forty-two thousand, six hundred sixty-five".