255891987 has 16 divisors (see below), whose sum is σ = 408261280. Its totient is φ = 157471776.

The previous prime is 255891983. The next prime is 255891989. The reversal of 255891987 is 789198552.

255891987 is a `hidden beast` number, since 2 + 558 + 9 + 1 + 9 + 87 = 666.

It is not a de Polignac number, because 255891987 - 2² = 255891983 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (255891983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 364168 + ... + 364869.

It is an arithmetic number, because the mean of its divisors is an integer number (25516330).

Almost surely, 2^255891987 is an apocalyptic number.

255891987 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

255891987 is a deficient number, since it is larger than the sum of its proper divisors (152369293).

255891987 is a wasteful number, since it uses less digits than its factorization.

255891987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 729059 (or 729053 counting only the distinct ones).

The product of its digits is 1814400, while the sum is 54.

The square root of 255891987 is about 15996.6242376321. The cubic root of 255891987 is about 634.8711061675.

The spelling of 255891987 in words is "two hundred fifty-five million, eight hundred ninety-one thousand, nine hundred eighty-seven".