257681399 has 4 divisors (see below), whose sum is σ = 257734464. Its totient is φ = 257628336.

The previous prime is 257681387. The next prime is 257681423. The reversal of 257681399 is 993186752.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 257681399 - 2¹⁶ = 257615863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257681329) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18422 + ... + 29235.

It is an arithmetic number, because the mean of its divisors is an integer number (64433616).

Almost surely, 2^257681399 is an apocalyptic number.

257681399 is a deficient number, since it is larger than the sum of its proper divisors (53065).

257681399 is an equidigital number, since it uses as much as digits as its factorization.

257681399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53064.

The product of its digits is 816480, while the sum is 50.

The square root of 257681399 is about 16052.4577245978. The cubic root of 257681399 is about 636.3475209704.

The spelling of 257681399 in words is "two hundred fifty-seven million, six hundred eighty-one thousand, three hundred ninety-nine".