255616681 has 2 divisors, whose sum is σ = 255616682. Its totient is φ = 255616680.

The previous prime is 255616619. The next prime is 255616693. The reversal of 255616681 is 186616552.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 227738281 + 27878400 = 15091^2 + 5280^2 .

It is a cyclic number.

It is not a de Polignac number, because 255616681 - 2¹³ = 255608489 is a prime.

It is a super-2 number, since 2×255616681² = 130679775210911522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (255613681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 127808340 + 127808341.

It is an arithmetic number, because the mean of its divisors is an integer number (127808341).

Almost surely, 2^255616681 is an apocalyptic number.

It is an amenable number.

255616681 is a deficient number, since it is larger than the sum of its proper divisors (1).

255616681 is an equidigital number, since it uses as much as digits as its factorization.

255616681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 86400, while the sum is 40.

The square root of 255616681 is about 15988.0167938366. The cubic root of 255616681 is about 634.6433452989.

The spelling of 255616681 in words is "two hundred fifty-five million, six hundred sixteen thousand, six hundred eighty-one".