255440639 has 4 divisors (see below), whose sum is σ = 255519360. Its totient is φ = 255361920.

The previous prime is 255440573. The next prime is 255440741. The reversal of 255440639 is 936044552.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 255440639 - 2²⁴ = 238663423 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 (255440539) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34274 + ... + 41055.

It is an arithmetic number, because the mean of its divisors is an integer number (63879840).

Almost surely, 2^255440639 is an apocalyptic number.

255440639 is a deficient number, since it is larger than the sum of its proper divisors (78721).

255440639 is an equidigital number, since it uses as much as digits as its factorization.

255440639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78720.

The product of its (nonzero) digits is 129600, while the sum is 38.

The square root of 255440639 is about 15982.5104098199. The cubic root of 255440639 is about 634.4976198829.

The spelling of 255440639 in words is "two hundred fifty-five million, four hundred forty thousand, six hundred thirty-nine".