257251398421 has 2 divisors, whose sum is σ = 257251398422. Its totient is φ = 257251398420.

The previous prime is 257251398403. The next prime is 257251398427. The reversal of 257251398421 is 124893152752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 189365095921 + 67886302500 = 435161^2 + 260550^2 .

It is a cyclic number.

It is not a de Polignac number, because 257251398421 - 2¹³ = 257251390229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257251398427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128625699210 + 128625699211.

It is an arithmetic number, because the mean of its divisors is an integer number (128625699211).

Almost surely, 2^257251398421 is an apocalyptic number.

It is an amenable number.

257251398421 is a deficient number, since it is larger than the sum of its proper divisors (1).

257251398421 is an equidigital number, since it uses as much as digits as its factorization.

257251398421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1209600, while the sum is 49.

The spelling of 257251398421 in words is "two hundred fifty-seven billion, two hundred fifty-one million, three hundred ninety-eight thousand, four hundred twenty-one".