1256573640 has 128 divisors (see below), whose sum is σ = 4396320000. Its totient is φ = 287207424.

The previous prime is 1256573639. The next prime is 1256573641. The reversal of 1256573640 is 463756521.

It is an interprime number because it is at equal distance from previous prime (1256573639) and next prime (1256573641).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1256573641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 25896 + ... + 56424.

It is an arithmetic number, because the mean of its divisors is an integer number (34346250).

Almost surely, 2^1256573640 is an apocalyptic number.

1256573640 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 1256573640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2198160000).

1256573640 is an abundant number, since it is smaller than the sum of its proper divisors (3139746360).

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

1256573640 is a wasteful number, since it uses less digits than its factorization.

1256573640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30564 (or 30546 counting only the distinct ones).

The product of its (nonzero) digits is 151200, while the sum is 39.

The square root of 1256573640 is about 35448.1824639854. The cubic root of 1256573640 is about 1079.1023748729.

The spelling of 1256573640 in words is "one billion, two hundred fifty-six million, five hundred seventy-three thousand, six hundred forty".