1555668665 has 16 divisors (see below), whose sum is σ = 1903003200. Its totient is φ = 1220521920.

The previous prime is 1555668661. The next prime is 1555668671. The reversal of 1555668665 is 5668665551.

It is not a de Polignac number, because 1555668665 - 2² = 1555668661 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1555668661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 98486 + ... + 113184.

It is an arithmetic number, because the mean of its divisors is an integer number (118937700).

Almost surely, 2^1555668665 is an apocalyptic number.

It is an amenable number.

1555668665 is a deficient number, since it is larger than the sum of its proper divisors (347334535).

1555668665 is a wasteful number, since it uses less digits than its factorization.

1555668665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15112.

The product of its digits is 6480000, while the sum is 53.

The square root of 1555668665 is about 39441.9657851887. The cubic root of 1555668665 is about 1158.7036312893.

The spelling of 1555668665 in words is "one billion, five hundred fifty-five million, six hundred sixty-eight thousand, six hundred sixty-five".