251225544021 has 4 divisors (see below), whose sum is σ = 334967392032. Its totient is φ = 167483696012.

The previous prime is 251225543981. The next prime is 251225544091. The reversal of 251225544021 is 120445522152.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-251225544021 is a prime.

It is a super-2 number, since 2×251225544021² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251225544091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41870924001 + ... + 41870924006.

It is an arithmetic number, because the mean of its divisors is an integer number (83741848008).

Almost surely, 2^251225544021 is an apocalyptic number.

It is an amenable number.

251225544021 is a deficient number, since it is larger than the sum of its proper divisors (83741848011).

251225544021 is an equidigital number, since it uses as much as digits as its factorization.

251225544021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83741848010.

The product of its (nonzero) digits is 32000, while the sum is 33.

The spelling of 251225544021 in words is "two hundred fifty-one billion, two hundred twenty-five million, five hundred forty-four thousand, twenty-one".