251415421 has 2 divisors, whose sum is σ = 251415422. Its totient is φ = 251415420.

The previous prime is 251415379. The next prime is 251415433. The reversal of 251415421 is 124514152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 193488100 + 57927321 = 13910^2 + 7611^2 .

It is a cyclic number.

It is not a de Polignac number, because 251415421 - 2¹⁹ = 250891133 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251415721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125707710 + 125707711.

It is an arithmetic number, because the mean of its divisors is an integer number (125707711).

Almost surely, 2^251415421 is an apocalyptic number.

It is an amenable number.

251415421 is a deficient number, since it is larger than the sum of its proper divisors (1).

251415421 is an equidigital number, since it uses as much as digits as its factorization.

251415421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1600, while the sum is 25.

The square root of 251415421 is about 15856.0846680383. The cubic root of 251415421 is about 631.1471674337.

Adding to 251415421 its reverse (124514152), we get a palindrome (375929573).

The spelling of 251415421 in words is "two hundred fifty-one million, four hundred fifteen thousand, four hundred twenty-one".