7959991 has 4 divisors (see below), whose sum is σ = 8572312. Its totient is φ = 7347672.

The previous prime is 7959983. The next prime is 7959997. The reversal of 7959991 is 1999597.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1999597 = 23 ⋅86939.

It is a cyclic number.

It is not a de Polignac number, because 7959991 - 2³ = 7959983 is a prime.

It is a super-2 number, since 2×7959991² = 126722913440162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7959997) 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, 306141 + ... + 306166.

It is an arithmetic number, because the mean of its divisors is an integer number (2143078).

Almost surely, 2^7959991 is an apocalyptic number.

7959991 is a deficient number, since it is larger than the sum of its proper divisors (612321).

7959991 is a wasteful number, since it uses less digits than its factorization.

7959991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 612320.

The product of its digits is 229635, while the sum is 49.

The square root of 7959991 is about 2821.3456009500. The cubic root of 7959991 is about 199.6660343117. Note that the first 3 decimals are identical.

The spelling of 7959991 in words is "seven million, nine hundred fifty-nine thousand, nine hundred ninety-one".