51581223225 has 225 divisors, whose sum is σ = 112556680863. Its totient is φ = 23351055840.

The previous prime is 51581223193. The next prime is 51581223229. The reversal of 51581223225 is 52232218515.

The square root of 51581223225 is 227115.

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

51581223225 is a `hidden beast` number, since 5 + 1 + 581 + 22 + 32 + 25 = 666.

It can be written as a sum of positive squares in only one way, i.e., 18569240361 + 33011982864 = 136269^2 + 181692^2 .

It is a tau number, because it is divible by the number of its divisors (225).

It is not a de Polignac number, because 51581223225 - 2⁵ = 51581223193 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51581223225.

It is not an unprimeable number, because it can be changed into a prime (51581223229) by changing a digit.

It is a polite number, since it can be written in 224 ways as a sum of consecutive naturals, for example, 500788524 + ... + 500788626.

Almost surely, 2^51581223225 is an apocalyptic number.

51581223225 is the 227115-th square number.

51581223225 is the 113558-th centered octagonal number.

It is an amenable number.

51581223225 is an abundant number, since it is smaller than the sum of its proper divisors (60975457638).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51581223225 is an frugal number, since it uses more digits than its factorization.

51581223225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256 (or 118 counting only the distinct ones).

The product of its digits is 48000, while the sum is 36.

Multiplying 51581223225 by its sum of digits (36), we get a square (1856924036100 = 1362690²).

The spelling of 51581223225 in words is "fifty-one billion, five hundred eighty-one million, two hundred twenty-three thousand, two hundred twenty-five".