251421013 has 2 divisors, whose sum is σ = 251421014. Its totient is φ = 251421012.

The previous prime is 251420999. The next prime is 251421019. The reversal of 251421013 is 310124152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 156300004 + 95121009 = 12502^2 + 9753^2 .

It is a cyclic number.

It is not a de Polignac number, because 251421013 - 2²⁵ = 217866581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251421019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125710506 + 125710507.

It is an arithmetic number, because the mean of its divisors is an integer number (125710507).

Almost surely, 2^251421013 is an apocalyptic number.

It is an amenable number.

251421013 is a deficient number, since it is larger than the sum of its proper divisors (1).

251421013 is an equidigital number, since it uses as much as digits as its factorization.

251421013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 251421013 is about 15856.2610031495. The cubic root of 251421013 is about 631.1518467394.

Adding to 251421013 its reverse (310124152), we get a palindrome (561545165).

The spelling of 251421013 in words is "two hundred fifty-one million, four hundred twenty-one thousand, thirteen".