155559561 has 16 divisors (see below), whose sum is σ = 210063360. Its totient is φ = 102387600.

The previous prime is 155559553. The next prime is 155559583. The reversal of 155559561 is 165955551.

It is not a de Polignac number, because 155559561 - 2³ = 155559553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (155559541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 147486 + ... + 148536.

It is an arithmetic number, because the mean of its divisors is an integer number (13128960).

Almost surely, 2^155559561 is an apocalyptic number.

It is an amenable number.

155559561 is a deficient number, since it is larger than the sum of its proper divisors (54503799).

155559561 is a wasteful number, since it uses less digits than its factorization.

155559561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1636.

The product of its digits is 168750, while the sum is 42.

The square root of 155559561 is about 12472.3518632213. The cubic root of 155559561 is about 537.8141647058.

It can be divided in two parts, 1555 and 59561, that added together give a palindrome (61116).

The spelling of 155559561 in words is "one hundred fifty-five million, five hundred fifty-nine thousand, five hundred sixty-one".