257216121 has 16 divisors (see below), whose sum is σ = 381760320. Its totient is φ = 171162720.

The previous prime is 257216117. The next prime is 257216131. The reversal of 257216121 is 121612752.

257216121 is a `hidden beast` number, since 25 + 7 + 21 + 612 + 1 = 666.

It is not a de Polignac number, because 257216121 - 2² = 257216117 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (257216111) 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 15 ways as a sum of consecutive naturals, for example, 6741 + ... + 23661.

It is an arithmetic number, because the mean of its divisors is an integer number (23860020).

Almost surely, 2^257216121 is an apocalyptic number.

It is an amenable number.

257216121 is a deficient number, since it is larger than the sum of its proper divisors (124544199).

257216121 is a wasteful number, since it uses less digits than its factorization.

257216121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17493 (or 17487 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 257216121 is about 16037.9587541557. The cubic root of 257216121 is about 635.9642868875.

Adding to 257216121 its reverse (121612752), we get a palindrome (378828873).

The spelling of 257216121 in words is "two hundred fifty-seven million, two hundred sixteen thousand, one hundred twenty-one".