251221133400225 has 24 divisors (see below), whose sum is σ = 439784760589920. Its totient is φ = 126103157157120.

The previous prime is 251221133400217. The next prime is 251221133400233. The reversal of 251221133400225 is 522004331122152.

It is an interprime number because it is at equal distance from previous prime (251221133400217) and next prime (251221133400233).

It is not a de Polignac number, because 251221133400225 - 2³ = 251221133400217 is a prime.

It is a super-2 number, since 2×251221133400225² (a number of 30 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 98518090255 + ... + 98518092804.

It is an arithmetic number, because the mean of its divisors is an integer number (18324365024580).

Almost surely, 2^{251221133400225} is an apocalyptic number.

251221133400225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

251221133400225 is a deficient number, since it is larger than the sum of its proper divisors (188563627189695).

251221133400225 is a wasteful number, since it uses less digits than its factorization.

251221133400225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197036183089 (or 197036183084 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 33.

Adding to 251221133400225 its reverse (522004331122152), we get a palindrome (773225464522377).

The spelling of 251221133400225 in words is "two hundred fifty-one trillion, two hundred twenty-one billion, one hundred thirty-three million, four hundred thousand, two hundred twenty-five".