7975991 has 4 divisors (see below), whose sum is σ = 8395800. Its totient is φ = 7556184.

The previous prime is 7975987. The next prime is 7975997. The reversal of 7975991 is 1995797.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 7975991 - 2² = 7975987 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 (7975997) 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, 209876 + ... + 209913.

It is an arithmetic number, because the mean of its divisors is an integer number (2098950).

Almost surely, 2^7975991 is an apocalyptic number.

7975991 is a deficient number, since it is larger than the sum of its proper divisors (419809).

7975991 is a wasteful number, since it uses less digits than its factorization.

7975991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 419808.

The product of its digits is 178605, while the sum is 47.

The square root of 7975991 is about 2824.1797039140. The cubic root of 7975991 is about 199.7997245156.

The spelling of 7975991 in words is "seven million, nine hundred seventy-five thousand, nine hundred ninety-one".