1256805456 has 40 divisors (see below), whose sum is σ = 3249226560. Its totient is φ = 418615296.

The previous prime is 1256805439. The next prime is 1256805457. The reversal of 1256805456 is 6545086521.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1256805457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58341 + ... + 76923.

It is an arithmetic number, because the mean of its divisors is an integer number (81230664).

Almost surely, 2^1256805456 is an apocalyptic number.

1256805456 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1256805456 is an abundant number, since it is smaller than the sum of its proper divisors (1992421104).

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

1256805456 is a wasteful number, since it uses less digits than its factorization.

1256805456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20003 (or 19997 counting only the distinct ones).

The product of its (nonzero) digits is 288000, while the sum is 42.

The square root of 1256805456 is about 35451.4521000198. The cubic root of 1256805456 is about 1079.1687293379.

The spelling of 1256805456 in words is "one billion, two hundred fifty-six million, eight hundred five thousand, four hundred fifty-six".