251213421 has 16 divisors (see below), whose sum is σ = 354368000. Its totient is φ = 157856688.

The previous prime is 251213419. The next prime is 251213453. The reversal of 251213421 is 124312152.

It is not a de Polignac number, because 251213421 - 2¹ = 251213419 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251213411) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 270 + ... + 22416.

It is an arithmetic number, because the mean of its divisors is an integer number (22148000).

Almost surely, 2^251213421 is an apocalyptic number.

It is an amenable number.

251213421 is a deficient number, since it is larger than the sum of its proper divisors (103154579).

251213421 is a wasteful number, since it uses less digits than its factorization.

251213421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22368.

The product of its digits is 480, while the sum is 21.

The square root of 251213421 is about 15849.7135936269. The cubic root of 251213421 is about 630.9780901790.

Adding to 251213421 its reverse (124312152), we get a palindrome (375525573).

The spelling of 251213421 in words is "two hundred fifty-one million, two hundred thirteen thousand, four hundred twenty-one".