256611840 has 80 divisors (see below), whose sum is σ = 820380528. Its totient is φ = 68427776.

The previous prime is 256611799. The next prime is 256611871. The reversal of 256611840 is 48116652.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9027 + ... + 24386.

Almost surely, 2^256611840 is an apocalyptic number.

256611840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256611840 is an abundant number, since it is smaller than the sum of its proper divisors (563768688).

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

256611840 is an equidigital number, since it uses as much as digits as its factorization.

256611840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33439 (or 33423 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 256611840 is about 16019.1085894316. The cubic root of 256611840 is about 635.4658701281.

The spelling of 256611840 in words is "two hundred fifty-six million, six hundred eleven thousand, eight hundred forty".