3975399891 has 10 divisors (see below), whose sum is σ = 5938560452. Its totient is φ = 2650266540.

The previous prime is 3975399853. The next prime is 3975399899. The reversal of 3975399891 is 1989935793.

3975399891 is a `hidden beast` number, since 3 + 9 + 7 + 539 + 9 + 8 + 91 = 666.

It is not a de Polignac number, because 3975399891 - 2¹³ = 3975391699 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3975399899) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 24539425 + ... + 24539586.

Almost surely, 2^3975399891 is an apocalyptic number.

3975399891 is a deficient number, since it is larger than the sum of its proper divisors (1963160561).

3975399891 is an equidigital number, since it uses as much as digits as its factorization.

3975399891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49079023 (or 49079014 counting only the distinct ones).

The product of its digits is 16533720, while the sum is 63.

The square root of 3975399891 is about 63050.7723267527. The cubic root of 3975399891 is about 1584.1401713938.

The spelling of 3975399891 in words is "three billion, nine hundred seventy-five million, three hundred ninety-nine thousand, eight hundred ninety-one".