3991422389 has 4 divisors (see below), whose sum is σ = 3991868556. Its totient is φ = 3990976224.

The previous prime is 3991422377. The next prime is 3991422431. The reversal of 3991422389 is 9832241993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9832241993 = 7 ⋅1404605999.

It can be written as a sum of positive squares in 2 ways, for example, as 1522326289 + 2469096100 = 39017^2 + 49690^2 .

It is a cyclic number.

It is not a de Polignac number, because 3991422389 - 2⁴ = 3991422373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3991422349) 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, 209384 + ... + 227649.

It is an arithmetic number, because the mean of its divisors is an integer number (997967139).

Almost surely, 2^3991422389 is an apocalyptic number.

It is an amenable number.

3991422389 is a deficient number, since it is larger than the sum of its proper divisors (446167).

3991422389 is an equidigital number, since it uses as much as digits as its factorization.

3991422389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446166.

The product of its digits is 839808, while the sum is 50.

The square root of 3991422389 is about 63177.7048411859. The cubic root of 3991422389 is about 1586.2655642062.

The spelling of 3991422389 in words is "three billion, nine hundred ninety-one million, four hundred twenty-two thousand, three hundred eighty-nine".