251530223121 has 24 divisors (see below), whose sum is σ = 365719197480. Its totient is φ = 166582137600.

The previous prime is 251530223047. The next prime is 251530223171. The reversal of 251530223121 is 121322035152.

251530223121 is a `hidden beast` number, since 2 + 5 + 1 + 530 + 2 + 2 + 3 + 121 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 54913360896 + 196616862225 = 234336^2 + 443415^2 .

It is not a de Polignac number, because 251530223121 - 2²⁹ = 250993352209 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (251530223171) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1450845 + ... + 1614933.

It is an arithmetic number, because the mean of its divisors is an integer number (15238299895).

Almost surely, 2^251530223121 is an apocalyptic number.

It is an amenable number.

251530223121 is a deficient number, since it is larger than the sum of its proper divisors (114188974359).

251530223121 is a wasteful number, since it uses less digits than its factorization.

251530223121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165217 (or 165214 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

Adding to 251530223121 its reverse (121322035152), we get a palindrome (372852258273).

The spelling of 251530223121 in words is "two hundred fifty-one billion, five hundred thirty million, two hundred twenty-three thousand, one hundred twenty-one".