255918021 has 8 divisors (see below), whose sum is σ = 341878560. Its totient is φ = 170284752.

The previous prime is 255917969. The next prime is 255918029. The reversal of 255918021 is 120819552.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 255918021 - 2¹⁴ = 255901637 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (255918029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79986 + ... + 83123.

It is an arithmetic number, because the mean of its divisors is an integer number (42734820).

Almost surely, 2^255918021 is an apocalyptic number.

It is an amenable number.

255918021 is a deficient number, since it is larger than the sum of its proper divisors (85960539).

255918021 is a wasteful number, since it uses less digits than its factorization.

255918021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163635.

The product of its (nonzero) digits is 7200, while the sum is 33.

The square root of 255918021 is about 15997.4379511220. The cubic root of 255918021 is about 634.8926356601.

The spelling of 255918021 in words is "two hundred fifty-five million, nine hundred eighteen thousand, twenty-one".