1256881920 has 576 divisors, whose sum is σ = 5086126080. Its totient is φ = 257900544.

The previous prime is 1256881907. The next prime is 1256881921. The reversal of 1256881920 is 291886521.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1256881921) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11746507 + ... + 11746613.

It is an arithmetic number, because the mean of its divisors is an integer number (8830080).

Almost surely, 2^1256881920 is an apocalyptic number.

1256881920 is a gapful number since it is divisible by the number (10) 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 1256881920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2543063040).

1256881920 is an abundant number, since it is smaller than the sum of its proper divisors (3829244160).

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

1256881920 is a wasteful number, since it uses less digits than its factorization.

1256881920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180 (or 166 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 42.

The square root of 1256881920 is about 35452.5305161705. The cubic root of 1256881920 is about 1079.1906144233.

The spelling of 1256881920 in words is "one billion, two hundred fifty-six million, eight hundred eighty-one thousand, nine hundred twenty".