257015981 has 4 divisors (see below), whose sum is σ = 257193600. Its totient is φ = 256838364.

The previous prime is 257015971. The next prime is 257016061. The reversal of 257015981 is 189510752.

257015981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 257015981 - 2¹⁸ = 256753837 is a prime.

It is a super-2 number, since 2×257015981² = 132114428978784722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257015971) 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, 86621 + ... + 89538.

It is an arithmetic number, because the mean of its divisors is an integer number (64298400).

Almost surely, 2^257015981 is an apocalyptic number.

It is an amenable number.

257015981 is a deficient number, since it is larger than the sum of its proper divisors (177619).

257015981 is a wasteful number, since it uses less digits than its factorization.

257015981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177618.

The product of its (nonzero) digits is 25200, while the sum is 38.

The square root of 257015981 is about 16031.7179678287. The cubic root of 257015981 is about 635.7992960374.

The spelling of 257015981 in words is "two hundred fifty-seven million, fifteen thousand, nine hundred eighty-one".