155566665 has 12 divisors (see below), whose sum is σ = 269648964. Its totient is φ = 82968864.

The previous prime is 155566639. The next prime is 155566673. The reversal of 155566665 is 566665551.

It can be written as a sum of positive squares in 2 ways, for example, as 122146704 + 33419961 = 11052^2 + 5781^2 .

It is not a de Polignac number, because 155566665 - 2⁵ = 155566633 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 3457037 = 155566665 / (1 + 5 + 5 + 5 + 6 + 6 + 6 + 6 + 5).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 155566665.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1728474 + ... + 1728563.

It is an arithmetic number, because the mean of its divisors is an integer number (22470747).

Almost surely, 2^155566665 is an apocalyptic number.

155566665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

155566665 is a deficient number, since it is larger than the sum of its proper divisors (114082299).

155566665 is a wasteful number, since it uses less digits than its factorization.

155566665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3457048 (or 3457045 counting only the distinct ones).

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

The square root of 155566665 is about 12472.6366498828. The cubic root of 155566665 is about 537.8223514386.

The spelling of 155566665 in words is "one hundred fifty-five million, five hundred sixty-six thousand, six hundred sixty-five".