3639521920 has 64 divisors (see below), whose sum is σ = 8715736800. Its totient is φ = 1453298688.

The previous prime is 3639521917. The next prime is 3639521969. The reversal of 3639521920 is 291259363.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×3639521920² = 26492239612320972800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (40).

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, 391567 + ... + 400753.

Almost surely, 2^3639521920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 3639521920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4357868400).

3639521920 is an abundant number, since it is smaller than the sum of its proper divisors (5076214880).

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

3639521920 is an equidigital number, since it uses as much as digits as its factorization.

3639521920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9825 (or 9813 counting only the distinct ones).

The product of its (nonzero) digits is 87480, while the sum is 40.

The square root of 3639521920 is about 60328.4503364706. The cubic root of 3639521920 is about 1538.2069872591.

The spelling of 3639521920 in words is "three billion, six hundred thirty-nine million, five hundred twenty-one thousand, nine hundred twenty".