251283421 has 2 divisors, whose sum is σ = 251283422. Its totient is φ = 251283420.

The previous prime is 251283353. The next prime is 251283449. The reversal of 251283421 is 124382152.

It is an a-pointer prime, because the next prime (251283449) can be obtained adding 251283421 to its sum of digits (28).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 193599396 + 57684025 = 13914^2 + 7595^2 .

It is a cyclic number.

It is not a de Polignac number, because 251283421 - 2⁷ = 251283293 is a prime.

It is a super-4 number, since 4×251283421⁴ (a number of 35 digits) contains 4444 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 251283421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251283451) 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, 125641710 + 125641711.

It is an arithmetic number, because the mean of its divisors is an integer number (125641711).

Almost surely, 2^251283421 is an apocalyptic number.

It is an amenable number.

251283421 is a deficient number, since it is larger than the sum of its proper divisors (1).

251283421 is an equidigital number, since it uses as much as digits as its factorization.

251283421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3840, while the sum is 28.

The square root of 251283421 is about 15851.9216816132. The cubic root of 251283421 is about 631.0366915657.

The spelling of 251283421 in words is "two hundred fifty-one million, two hundred eighty-three thousand, four hundred twenty-one".