1656366640 has 20 divisors (see below), whose sum is σ = 3851052624. Its totient is φ = 662546624.

The previous prime is 1656366637. The next prime is 1656366703. The reversal of 1656366640 is 466636561.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×1656366640² = 5487100892209779200, which contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 10352212 + ... + 10352371.

Almost surely, 2^1656366640 is an apocalyptic number.

1656366640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1656366640 is an abundant number, since it is smaller than the sum of its proper divisors (2194685984).

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

1656366640 is a wasteful number, since it uses less digits than its factorization.

1656366640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20704596 (or 20704590 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 43.

The square root of 1656366640 is about 40698.4844926688. The cubic root of 1656366640 is about 1183.1836463881.

The spelling of 1656366640 in words is "one billion, six hundred fifty-six million, three hundred sixty-six thousand, six hundred forty".