3990639121 has 4 divisors (see below), whose sum is σ = 4560730432. Its totient is φ = 3420547812.

The previous prime is 3990639053. The next prime is 3990639131. The reversal of 3990639121 is 1219360993.

3990639121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3990639121 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (3990639131) 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, 285045645 + ... + 285045658.

It is an arithmetic number, because the mean of its divisors is an integer number (1140182608).

Almost surely, 2^3990639121 is an apocalyptic number.

It is an amenable number.

3990639121 is a deficient number, since it is larger than the sum of its proper divisors (570091311).

3990639121 is an equidigital number, since it uses as much as digits as its factorization.

3990639121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 570091310.

The product of its (nonzero) digits is 78732, while the sum is 43.

The square root of 3990639121 is about 63171.5056097288. The cubic root of 3990639121 is about 1586.1617956565.

The spelling of 3990639121 in words is "three billion, nine hundred ninety million, six hundred thirty-nine thousand, one hundred twenty-one".