2639660840 has 16 divisors (see below), whose sum is σ = 5939236980. Its totient is φ = 1055864320.

The previous prime is 2639660809. The next prime is 2639660857. The reversal of 2639660840 is 480669362.

It can be written as a sum of positive squares in 2 ways, for example, as 2420443204 + 219217636 = 49198^2 + 14806^2 .

It is a junction number, because it is equal to n+sod(n) for n = 2639660791 and 2639660800.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32995721 + ... + 32995800.

Almost surely, 2^2639660840 is an apocalyptic number.

2639660840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2639660840 is an abundant number, since it is smaller than the sum of its proper divisors (3299576140).

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

2639660840 is a wasteful number, since it uses less digits than its factorization.

2639660840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65991532 (or 65991528 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 44.

The square root of 2639660840 is about 51377.6297623781. The cubic root of 2639660840 is about 1382.0254581357.

The spelling of 2639660840 in words is "two billion, six hundred thirty-nine million, six hundred sixty thousand, eight hundred forty".