256247040 has 144 divisors (see below), whose sum is σ = 935399808. Its totient is φ = 58564608.

The previous prime is 256247027. The next prime is 256247041. The reversal of 256247040 is 40742652.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 256246989 and 256247007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256247041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22114 + ... + 31646.

It is an arithmetic number, because the mean of its divisors is an integer number (6495832).

Almost surely, 2^256247040 is an apocalyptic number.

256247040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256247040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (467699904).

256247040 is an abundant number, since it is smaller than the sum of its proper divisors (679152768).

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

256247040 is an equidigital number, since it uses as much as digits as its factorization.

256247040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9564 (or 9550 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 30.

The square root of 256247040 is about 16007.7181384481. The cubic root of 256247040 is about 635.1646007255.

Adding to 256247040 its reverse (40742652), we get a palindrome (296989692).

The spelling of 256247040 in words is "two hundred fifty-six million, two hundred forty-seven thousand, forty".