255428812821 has 32 divisors (see below), whose sum is σ = 419341466880. Its totient is φ = 134675034624.

The previous prime is 255428812819. The next prime is 255428812831. The reversal of 255428812821 is 128218824552.

It is not a de Polignac number, because 255428812821 - 2¹ = 255428812819 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (255428812831) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 457795 + ... + 848783.

It is an arithmetic number, because the mean of its divisors is an integer number (13104420840).

Almost surely, 2^255428812821 is an apocalyptic number.

255428812821 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

255428812821 is a deficient number, since it is larger than the sum of its proper divisors (163912654059).

255428812821 is a wasteful number, since it uses less digits than its factorization.

255428812821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393405.

The product of its digits is 819200, while the sum is 48.

The spelling of 255428812821 in words is "two hundred fifty-five billion, four hundred twenty-eight million, eight hundred twelve thousand, eight hundred twenty-one".