257720457 has 8 divisors (see below), whose sum is σ = 351618784. Its totient is φ = 167817888.

The previous prime is 257720423. The next prime is 257720461. The reversal of 257720457 is 754027752.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-257720457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (257720417) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 998788 + ... + 999045.

It is an arithmetic number, because the mean of its divisors is an integer number (43952348).

Almost surely, 2^257720457 is an apocalyptic number.

It is an amenable number.

257720457 is a deficient number, since it is larger than the sum of its proper divisors (93898327).

257720457 is a wasteful number, since it uses less digits than its factorization.

257720457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1997879.

The product of its (nonzero) digits is 137200, while the sum is 39.

The square root of 257720457 is about 16053.6742523324. The cubic root of 257720457 is about 636.3796707568.

The spelling of 257720457 in words is "two hundred fifty-seven million, seven hundred twenty thousand, four hundred fifty-seven".