257201721 has 24 divisors (see below), whose sum is σ = 449564544. Its totient is φ = 138326400.

The previous prime is 257201701. The next prime is 257201753. The reversal of 257201721 is 127102752.

It is not a de Polignac number, because 257201721 - 2⁶ = 257201657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (257201701) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 119005 + ... + 121146.

It is an arithmetic number, because the mean of its divisors is an integer number (18731856).

Almost surely, 2^257201721 is an apocalyptic number.

257201721 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

257201721 is a deficient number, since it is larger than the sum of its proper divisors (192362823).

257201721 is a wasteful number, since it uses less digits than its factorization.

257201721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240181 (or 240178 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 27.

The square root of 257201721 is about 16037.5098129354. The cubic root of 257201721 is about 635.9524187140.

The spelling of 257201721 in words is "two hundred fifty-seven million, two hundred one thousand, seven hundred twenty-one".