257106921 has 4 divisors (see below), whose sum is σ = 342809232. Its totient is φ = 171404612.

The previous prime is 257106919. The next prime is 257106923. The reversal of 257106921 is 129601752.

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 an interprime number because it is at equal distance from previous prime (257106919) and next prime (257106923).

It is a cyclic number.

It is not a de Polignac number, because 257106921 - 2¹ = 257106919 is a prime.

It is a super-2 number, since 2×257106921² = 132207937652200482, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (257106923) 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, 42851151 + ... + 42851156.

It is an arithmetic number, because the mean of its divisors is an integer number (85702308).

Almost surely, 2^257106921 is an apocalyptic number.

It is an amenable number.

257106921 is a deficient number, since it is larger than the sum of its proper divisors (85702311).

257106921 is an equidigital number, since it uses as much as digits as its factorization.

257106921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85702310.

The product of its (nonzero) digits is 7560, while the sum is 33.

The square root of 257106921 is about 16034.5539694748. The cubic root of 257106921 is about 635.8742755123.

The spelling of 257106921 in words is "two hundred fifty-seven million, one hundred six thousand, nine hundred twenty-one".