61566228352225 has 81 divisors (see below), whose sum is σ = 78863068191243. Its totient is φ = 47678081648640.

The previous prime is 61566228352159. The next prime is 61566228352333. The reversal of 61566228352225 is 52225382266516.

The square root of 61566228352225 is 7846415.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 13 ways, for example, as 26642950745761 + 34923277606464 = 5161681^2 + 5909592^2 .

It is not a de Polignac number, because 61566228352225 - 2²⁷ = 61566094134497 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 318996001729 + ... + 318996001921.

Almost surely, 2^{61566228352225} is an apocalyptic number.

61566228352225 is the 7846415-th square number.

61566228352225 is the 3923208-th centered octagonal number.

It is an amenable number.

61566228352225 is a deficient number, since it is larger than the sum of its proper divisors (17296839839018).

61566228352225 is an frugal number, since it uses more digits than its factorization.

61566228352225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 836 (or 418 counting only the distinct ones).

The product of its digits is 20736000, while the sum is 55.

The spelling of 61566228352225 in words is "sixty-one trillion, five hundred sixty-six billion, two hundred twenty-eight million, three hundred fifty-two thousand, two hundred twenty-five".