155665665 has 32 divisors (see below), whose sum is σ = 277482240. Its totient is φ = 82798848.

The previous prime is 155665661. The next prime is 155665667. The reversal of 155665665 is 566566551.

It is not a de Polignac number, because 155665665 - 2² = 155665661 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 155665665.

It is not an unprimeable number, because it can be changed into a prime (155665661) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 57124 + ... + 59786.

It is an arithmetic number, because the mean of its divisors is an integer number (8671320).

Almost surely, 2^155665665 is an apocalyptic number.

155665665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

155665665 is a deficient number, since it is larger than the sum of its proper divisors (121816575).

155665665 is a wasteful number, since it uses less digits than its factorization.

155665665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3110 (or 3104 counting only the distinct ones).

The product of its digits is 810000, while the sum is 45.

The square root of 155665665 is about 12476.6047064095. The cubic root of 155665665 is about 537.9364142685.

The spelling of 155665665 in words is "one hundred fifty-five million, six hundred sixty-five thousand, six hundred sixty-five".