257430779721 has 8 divisors (see below), whose sum is σ = 381378932960. Its totient is φ = 171620519796.

The previous prime is 257430779699. The next prime is 257430779729. The reversal of 257430779721 is 127977034752.

257430779721 is a `hidden beast` number, since 2 + 57 + 430 + 77 + 97 + 2 + 1 = 666.

It is not a de Polignac number, because 257430779721 - 2⁵ = 257430779689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (257430779729) 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, 4767236635 + ... + 4767236688.

It is an arithmetic number, because the mean of its divisors is an integer number (47672366620).

Almost surely, 2^257430779721 is an apocalyptic number.

It is an amenable number.

257430779721 is a deficient number, since it is larger than the sum of its proper divisors (123948153239).

257430779721 is an equidigital number, since it uses as much as digits as its factorization.

257430779721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9534473332 (or 9534473326 counting only the distinct ones).

The product of its (nonzero) digits is 5186160, while the sum is 54.

The spelling of 257430779721 in words is "two hundred fifty-seven billion, four hundred thirty million, seven hundred seventy-nine thousand, seven hundred twenty-one".