1636660640 has 48 divisors (see below), whose sum is σ = 3875172840. Its totient is φ = 653214720.

The previous prime is 1636660633. The next prime is 1636660679. The reversal of 1636660640 is 460666361.

It can be written as a sum of positive squares in 4 ways, for example, as 1301477776 + 335182864 = 36076^2 + 18308^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1636660594 and 1636660603.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62666 + ... + 84854.

Almost surely, 2^1636660640 is an apocalyptic number.

1636660640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1636660640 is an abundant number, since it is smaller than the sum of its proper divisors (2238512200).

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

1636660640 is a wasteful number, since it uses less digits than its factorization.

1636660640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22665 (or 22657 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 38.

The square root of 1636660640 is about 40455.6626444309. The cubic root of 1636660640 is about 1178.4727536575.

The spelling of 1636660640 in words is "one billion, six hundred thirty-six million, six hundred sixty thousand, six hundred forty".