255619781 has 4 divisors (see below), whose sum is σ = 257335500. Its totient is φ = 253904064.

The previous prime is 255619759. The next prime is 255619813. The reversal of 255619781 is 187916552.

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

It can be written as a sum of positive squares in 2 ways, for example, as 150454756 + 105165025 = 12266^2 + 10255^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-255619781 is a prime.

It is a super-2 number, since 2×255619781² = 130682944876975922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (255619181) 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, 857636 + ... + 857933.

It is an arithmetic number, because the mean of its divisors is an integer number (64333875).

Almost surely, 2^255619781 is an apocalyptic number.

It is an amenable number.

255619781 is a deficient number, since it is larger than the sum of its proper divisors (1715719).

255619781 is a wasteful number, since it uses less digits than its factorization.

255619781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1715718.

The product of its digits is 151200, while the sum is 44.

The square root of 255619781 is about 15988.1137411516. The cubic root of 255619781 is about 634.6459108415.

The spelling of 255619781 in words is "two hundred fifty-five million, six hundred nineteen thousand, seven hundred eighty-one".