1256026640 has 160 divisors (see below), whose sum is σ = 3407567616. Its totient is φ = 425492480.

The previous prime is 1256026631. The next prime is 1256026687. The reversal of 1256026640 is 466206521.

It is a junction number, because it is equal to n+sod(n) for n = 1256026597 and 1256026606.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1690109 + ... + 1690851.

Almost surely, 2^1256026640 is an apocalyptic number.

1256026640 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 1256026640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1703783808).

1256026640 is an abundant number, since it is smaller than the sum of its proper divisors (2151540976).

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

1256026640 is a wasteful number, since it uses less digits than its factorization.

1256026640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 897 (or 891 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 1256026640 is about 35440.4661368893. The cubic root of 1256026640 is about 1078.9457705294.

The spelling of 1256026640 in words is "one billion, two hundred fifty-six million, twenty-six thousand, six hundred forty".