255906640 has 40 divisors (see below), whose sum is σ = 649074528. Its totient is φ = 93056640.

The previous prime is 255906589. The next prime is 255906641. The reversal of 255906640 is 46609552.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 255906640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (255906641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 144522 + ... + 146281.

Almost surely, 2^255906640 is an apocalyptic number.

255906640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

255906640 is an abundant number, since it is smaller than the sum of its proper divisors (393167888).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

255906640 is a wasteful number, since it uses less digits than its factorization.

255906640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 290827 (or 290821 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 37.

The square root of 255906640 is about 15997.0822339575. The cubic root of 255906640 is about 634.8832240261.

The spelling of 255906640 in words is "two hundred fifty-five million, nine hundred six thousand, six hundred forty".