3991438889 has 4 divisors (see below), whose sum is σ = 4201514640. Its totient is φ = 3781363140.

The previous prime is 3991438877. The next prime is 3991438901. The reversal of 3991438889 is 9888341993.

3991438889 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 an interprime number because it is at equal distance from previous prime (3991438877) and next prime (3991438901).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3991438889 is a prime.

It is a super-3 number, since 3×3991438889³ (a number of 30 digits) contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3991438189) 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, 105037847 + ... + 105037884.

It is an arithmetic number, because the mean of its divisors is an integer number (1050378660).

Almost surely, 2^3991438889 is an apocalyptic number.

It is an amenable number.

3991438889 is a deficient number, since it is larger than the sum of its proper divisors (210075751).

3991438889 is a wasteful number, since it uses less digits than its factorization.

3991438889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210075750.

The product of its digits is 13436928, while the sum is 62.

The square root of 3991438889 is about 63177.8354250919. The cubic root of 3991438889 is about 1586.2677500056.

The spelling of 3991438889 in words is "three billion, nine hundred ninety-one million, four hundred thirty-eight thousand, eight hundred eighty-nine".