257720420 has 24 divisors (see below), whose sum is σ = 546471744. Its totient is φ = 102086496.

The previous prime is 257720417. The next prime is 257720423. The reversal of 257720420 is 24027752.

It is an interprime number because it is at equal distance from previous prime (257720417) and next prime (257720423).

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (257720423) 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, 60494 + ... + 64613.

It is an arithmetic number, because the mean of its divisors is an integer number (22769656).

Almost surely, 2^257720420 is an apocalyptic number.

257720420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

257720420 is an abundant number, since it is smaller than the sum of its proper divisors (288751324).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

257720420 is a wasteful number, since it uses less digits than its factorization.

257720420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125219 (or 125217 counting only the distinct ones).

The product of its (nonzero) digits is 7840, while the sum is 29.

The square root of 257720420 is about 16053.6730999482. The cubic root of 257720420 is about 636.3796403025.

The spelling of 257720420 in words is "two hundred fifty-seven million, seven hundred twenty thousand, four hundred twenty".