7717991 has 4 divisors (see below), whose sum is σ = 7804800. Its totient is φ = 7631184.

The previous prime is 7717981. The next prime is 7717993. The reversal of 7717991 is 1997177.

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 7717991 - 2¹⁰ = 7716967 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 (7717993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43271 + ... + 43448.

It is an arithmetic number, because the mean of its divisors is an integer number (1951200).

Almost surely, 2^7717991 is an apocalyptic number.

7717991 is a deficient number, since it is larger than the sum of its proper divisors (86809).

7717991 is an equidigital number, since it uses as much as digits as its factorization.

7717991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86808.

The product of its digits is 27783, while the sum is 41.

The square root of 7717991 is about 2778.1272469057. The cubic root of 7717991 is about 197.6217568940.

The spelling of 7717991 in words is "seven million, seven hundred seventeen thousand, nine hundred ninety-one".