257661000 has 160 divisors (see below), whose sum is σ = 900951480. Its totient is φ = 68688000.

The previous prime is 257660987. The next prime is 257661017. The reversal of 257661000 is 166752.

257661000 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 25220484 + 232440516 = 5022^2 + 15246^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 79410 + ... + 82590.

Almost surely, 2^257661000 is an apocalyptic number.

257661000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 257661000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (450475740).

257661000 is an abundant number, since it is smaller than the sum of its proper divisors (643290480).

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

257661000 is a wasteful number, since it uses less digits than its factorization.

257661000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3214 (or 3191 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 257661000 is about 16051.8223264525. The cubic root of 257661000 is about 636.3307286632.

The spelling of 257661000 in words is "two hundred fifty-seven million, six hundred sixty-one thousand".