257420729 has 4 divisors (see below), whose sum is σ = 264378084. Its totient is φ = 250463376.

The previous prime is 257420701. The next prime is 257420731. The reversal of 257420729 is 927024752.

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

It can be written as a sum of positive squares in 2 ways, for example, as 226562704 + 30858025 = 15052^2 + 5555^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257420729 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 257420692 and 257420701.

It is not an unprimeable number, because it can be changed into a prime (257420929) 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, 3478622 + ... + 3478695.

It is an arithmetic number, because the mean of its divisors is an integer number (66094521).

Almost surely, 2^257420729 is an apocalyptic number.

It is an amenable number.

257420729 is a deficient number, since it is larger than the sum of its proper divisors (6957355).

257420729 is an equidigital number, since it uses as much as digits as its factorization.

257420729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6957354.

The product of its (nonzero) digits is 70560, while the sum is 38.

The square root of 257420729 is about 16044.3363527445. The cubic root of 257420729 is about 636.1328726050.

The spelling of 257420729 in words is "two hundred fifty-seven million, four hundred twenty thousand, seven hundred twenty-nine".