255647821 has 12 divisors (see below), whose sum is σ = 301993920. Its totient is φ = 214528080.

The previous prime is 255647761. The next prime is 255647879. The reversal of 255647821 is 128746552.

It is not a de Polignac number, because 255647821 - 2¹⁵ = 255615053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (255647881) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 66901 + ... + 70618.

It is an arithmetic number, because the mean of its divisors is an integer number (25166160).

Almost surely, 2^255647821 is an apocalyptic number.

It is an amenable number.

255647821 is a deficient number, since it is larger than the sum of its proper divisors (46346099).

255647821 is a wasteful number, since it uses less digits than its factorization.

255647821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137556 (or 137543 counting only the distinct ones).

The product of its digits is 134400, while the sum is 40.

The square root of 255647821 is about 15988.9906185475. The cubic root of 255647821 is about 634.6691156454.

The spelling of 255647821 in words is "two hundred fifty-five million, six hundred forty-seven thousand, eight hundred twenty-one".