1256812380 has 144 divisors (see below), whose sum is σ = 4249234080. Its totient is φ = 298819584.

The previous prime is 1256812357. The next prime is 1256812421. The reversal of 1256812380 is 832186521.

It is a happy number.

1256812380 is a `hidden beast` number, since 1 + 2 + 568 + 12 + 3 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 47332 + ... + 68948.

It is an arithmetic number, because the mean of its divisors is an integer number (29508570).

Almost surely, 2^1256812380 is an apocalyptic number.

1256812380 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 1256812380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2124617040).

1256812380 is an abundant number, since it is smaller than the sum of its proper divisors (2992421700).

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

1256812380 is a wasteful number, since it uses less digits than its factorization.

1256812380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21668 (or 21663 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 1256812380 is about 35451.5497545594. The cubic root of 1256812380 is about 1079.1707111218.

The spelling of 1256812380 in words is "one billion, two hundred fifty-six million, eight hundred twelve thousand, three hundred eighty".