561000155 has 4 divisors (see below), whose sum is σ = 673200192. Its totient is φ = 448800120.

The previous prime is 561000133. The next prime is 561000163. The reversal of 561000155 is 551000165.

561000155 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 551000165 = 5 ⋅110200033.

It is not a de Polignac number, because 561000155 - 2⁶ = 561000091 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 561000155.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56100011 + ... + 56100020.

It is an arithmetic number, because the mean of its divisors is an integer number (168300048).

Almost surely, 2^561000155 is an apocalyptic number.

561000155 is a deficient number, since it is larger than the sum of its proper divisors (112200037).

561000155 is a wasteful number, since it uses less digits than its factorization.

561000155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112200036.

The product of its (nonzero) digits is 750, while the sum is 23.

The square root of 561000155 is about 23685.4418367064. The cubic root of 561000155 is about 824.7474733694.

The spelling of 561000155 in words is "five hundred sixty-one million, one hundred fifty-five", and thus it is an aban number.