257221645 has 16 divisors (see below), whose sum is σ = 328287168. Its totient is φ = 192805120.

The previous prime is 257221637. The next prime is 257221681. The reversal of 257221645 is 546122752.

257221645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 257221645 - 2³ = 257221637 is a prime.

It is a super-3 number, since 3×257221645³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 257221645.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12630 + ... + 25960.

It is an arithmetic number, because the mean of its divisors is an integer number (20517948).

Almost surely, 2^257221645 is an apocalyptic number.

It is an amenable number.

257221645 is a deficient number, since it is larger than the sum of its proper divisors (71065523).

257221645 is a wasteful number, since it uses less digits than its factorization.

257221645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13580.

The product of its digits is 33600, while the sum is 34.

The square root of 257221645 is about 16038.1309696610. The cubic root of 257221645 is about 635.9688395332.

The spelling of 257221645 in words is "two hundred fifty-seven million, two hundred twenty-one thousand, six hundred forty-five".