1640426256 has 400 divisors, whose sum is σ = 5915176960. Its totient is φ = 428302080.

The previous prime is 1640426243. The next prime is 1640426257. The reversal of 1640426256 is 6526240461.

1640426256 is a `hidden beast` number, since 1 + 640 + 4 + 2 + 6 + 2 + 5 + 6 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is a self number, because there is not a number n which added to its sum of digits gives 1640426256.

It is not an unprimeable number, because it can be changed into a prime (1640426257) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 5343255 + ... + 5343561.

Almost surely, 2^1640426256 is an apocalyptic number.

1640426256 is a gapful number since it is divisible by the number (16) 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 1640426256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2957588480).

1640426256 is an abundant number, since it is smaller than the sum of its proper divisors (4274750704).

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

1640426256 is a wasteful number, since it uses less digits than its factorization.

1640426256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384 (or 369 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The square root of 1640426256 is about 40502.1759415466. The cubic root of 1640426256 is about 1179.3758683497.

The spelling of 1640426256 in words is "one billion, six hundred forty million, four hundred twenty-six thousand, two hundred fifty-six".