7651991 has 4 divisors (see below), whose sum is σ = 7683984. Its totient is φ = 7620000.

The previous prime is 7651961. The next prime is 7651993. The reversal of 7651991 is 1991567.

7651991 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7651991 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 (7651993) 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, 15635 + ... + 16116.

It is an arithmetic number, because the mean of its divisors is an integer number (1920996).

Almost surely, 2^7651991 is an apocalyptic number.

7651991 is a deficient number, since it is larger than the sum of its proper divisors (31993).

7651991 is a wasteful number, since it uses less digits than its factorization.

7651991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31992.

The product of its digits is 17010, while the sum is 38.

The square root of 7651991 is about 2766.2232375569. The cubic root of 7651991 is about 197.0568260915.

The spelling of 7651991 in words is "seven million, six hundred fifty-one thousand, nine hundred ninety-one".