1640320656 has 160 divisors (see below), whose sum is σ = 4719614592. Its totient is φ = 487710720.

The previous prime is 1640320637. The next prime is 1640320663. The reversal of 1640320656 is 6560230461.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3031746 + ... + 3032286.

Almost surely, 2^1640320656 is an apocalyptic number.

1640320656 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 1640320656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2359807296).

1640320656 is an abundant number, since it is smaller than the sum of its proper divisors (3079293936).

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

1640320656 is a wasteful number, since it uses less digits than its factorization.

1640320656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 721 (or 715 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 33.

The square root of 1640320656 is about 40500.8722869027. The cubic root of 1640320656 is about 1179.3505609509.

The spelling of 1640320656 in words is "one billion, six hundred forty million, three hundred twenty thousand, six hundred fifty-six".