3991387397 has 8 divisors (see below), whose sum is σ = 4030963200. Its totient is φ = 3951865584.

The previous prime is 3991387339. The next prime is 3991387429. The reversal of 3991387397 is 7937831993.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3991387397 - 2²⁴ = 3974610181 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 (3991387307) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 144128 + ... + 169574.

It is an arithmetic number, because the mean of its divisors is an integer number (503870400).

Almost surely, 2^3991387397 is an apocalyptic number.

It is an amenable number.

3991387397 is a deficient number, since it is larger than the sum of its proper divisors (39575803).

3991387397 is a wasteful number, since it uses less digits than its factorization.

3991387397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26995.

The product of its digits is 7715736, while the sum is 59.

The square root of 3991387397 is about 63177.4279074418. The cubic root of 3991387397 is about 1586.2609287020.

The spelling of 3991387397 in words is "three billion, nine hundred ninety-one million, three hundred eighty-seven thousand, three hundred ninety-seven".