155636561 has 12 divisors (see below), whose sum is σ = 163511040. Its totient is φ = 148126440.

The previous prime is 155636519. The next prime is 155636563. The reversal of 155636561 is 165636551.

It is not a de Polignac number, because 155636561 - 2¹⁰ = 155635537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155636563) 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 11 ways as a sum of consecutive naturals, for example, 125816 + ... + 127046.

It is an arithmetic number, because the mean of its divisors is an integer number (13625920).

Almost surely, 2^155636561 is an apocalyptic number.

It is an amenable number.

155636561 is a deficient number, since it is larger than the sum of its proper divisors (7874479).

155636561 is a wasteful number, since it uses less digits than its factorization.

155636561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1516 (or 1493 counting only the distinct ones).

The product of its digits is 81000, while the sum is 38.

The square root of 155636561 is about 12475.4383089333. The cubic root of 155636561 is about 537.9028871209.

The spelling of 155636561 in words is "one hundred fifty-five million, six hundred thirty-six thousand, five hundred sixty-one".