255721539 has 4 divisors (see below), whose sum is σ = 340962056. Its totient is φ = 170481024.

The previous prime is 255721493. The next prime is 255721549. The reversal of 255721539 is 935127552.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 255721539 - 2⁹ = 255721027 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 255721497 and 255721506.

It is not an unprimeable number, because it can be changed into a prime (255721549) 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, 42620254 + ... + 42620259.

It is an arithmetic number, because the mean of its divisors is an integer number (85240514).

Almost surely, 2^255721539 is an apocalyptic number.

255721539 is a deficient number, since it is larger than the sum of its proper divisors (85240517).

255721539 is an equidigital number, since it uses as much as digits as its factorization.

255721539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85240516.

The product of its digits is 94500, while the sum is 39.

The square root of 255721539 is about 15991.2957261130. The cubic root of 255721539 is about 634.7301136769.

The spelling of 255721539 in words is "two hundred fifty-five million, seven hundred twenty-one thousand, five hundred thirty-nine".