257821423 has 2 divisors, whose sum is σ = 257821424. Its totient is φ = 257821422.

The previous prime is 257821411. The next prime is 257821453. The reversal of 257821423 is 324128752.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 257821423 - 2⁵ = 257821391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257821453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128910711 + 128910712.

It is an arithmetic number, because the mean of its divisors is an integer number (128910712).

Almost surely, 2^257821423 is an apocalyptic number.

257821423 is a deficient number, since it is larger than the sum of its proper divisors (1).

257821423 is an equidigital number, since it uses as much as digits as its factorization.

257821423 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26880, while the sum is 34.

The square root of 257821423 is about 16056.8185827704. The cubic root of 257821423 is about 636.4627637868.

The spelling of 257821423 in words is "two hundred fifty-seven million, eight hundred twenty-one thousand, four hundred twenty-three".