255191721 has 16 divisors (see below), whose sum is σ = 356052480. Its totient is φ = 162380160.

The previous prime is 255191711. The next prime is 255191737. The reversal of 255191721 is 127191552.

It is not a de Polignac number, because 255191721 - 2¹⁰ = 255190697 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (255191711) 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, 12006 + ... + 25583.

It is an arithmetic number, because the mean of its divisors is an integer number (22253280).

Almost surely, 2^255191721 is an apocalyptic number.

It is an amenable number.

255191721 is a deficient number, since it is larger than the sum of its proper divisors (100860759).

255191721 is a wasteful number, since it uses less digits than its factorization.

255191721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37696.

The product of its digits is 6300, while the sum is 33.

The square root of 255191721 is about 15974.7213121231. The cubic root of 255191721 is about 634.2914542957.

The spelling of 255191721 in words is "two hundred fifty-five million, one hundred ninety-one thousand, seven hundred twenty-one".