257661620 has 24 divisors (see below), whose sum is σ = 551300904. Its totient is φ = 101119616.

The previous prime is 257661601. The next prime is 257661623. The reversal of 257661620 is 26166752.

It can be written as a sum of positive squares in 4 ways, for example, as 58400164 + 199261456 = 7642^2 + 14116^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257661623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 120479 + ... + 122598.

It is an arithmetic number, because the mean of its divisors is an integer number (22970871).

Almost surely, 2^257661620 is an apocalyptic number.

257661620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

257661620 is an abundant number, since it is smaller than the sum of its proper divisors (293639284).

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

257661620 is a wasteful number, since it uses less digits than its factorization.

257661620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243139 (or 243137 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 35.

The square root of 257661620 is about 16051.8416388899. The cubic root of 257661620 is about 636.3312390557.

The spelling of 257661620 in words is "two hundred fifty-seven million, six hundred sixty-one thousand, six hundred twenty".