3639138820 has 12 divisors (see below), whose sum is σ = 7642191564. Its totient is φ = 1455655520.

The previous prime is 3639138781. The next prime is 3639138823. The reversal of 3639138820 is 288319363.

It can be written as a sum of positive squares in 2 ways, for example, as 1403551296 + 2235587524 = 37464^2 + 47282^2 .

It is not an unprimeable number, because it can be changed into a prime (3639138823) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 90978451 + ... + 90978490.

It is an arithmetic number, because the mean of its divisors is an integer number (636849297).

Almost surely, 2^3639138820 is an apocalyptic number.

It is an amenable number.

3639138820 is an abundant number, since it is smaller than the sum of its proper divisors (4003052744).

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

3639138820 is a wasteful number, since it uses less digits than its factorization.

3639138820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181956950 (or 181956948 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 43.

The square root of 3639138820 is about 60325.2751340597. The cubic root of 3639138820 is about 1538.1530142568.

The spelling of 3639138820 in words is "three billion, six hundred thirty-nine million, one hundred thirty-eight thousand, eight hundred twenty".