561521155 has 16 divisors (see below), whose sum is σ = 763852320. Its totient is φ = 392836608.

The previous prime is 561521143. The next prime is 561521159. The reversal of 561521155 is 551125165.

It is a cyclic number.

It is not a de Polignac number, because 561521155 - 2⁷ = 561521027 is a prime.

It is not an unprimeable number, because it can be changed into a prime (561521159) 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, 226102 + ... + 228571.

It is an arithmetic number, because the mean of its divisors is an integer number (47740770).

Almost surely, 2^561521155 is an apocalyptic number.

561521155 is a deficient number, since it is larger than the sum of its proper divisors (202331165).

561521155 is a wasteful number, since it uses less digits than its factorization.

561521155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454710.

The product of its digits is 7500, while the sum is 31.

The square root of 561521155 is about 23696.4376014624. The cubic root of 561521155 is about 825.0027082862.

The spelling of 561521155 in words is "five hundred sixty-one million, five hundred twenty-one thousand, one hundred fifty-five".