7991651 has 4 divisors (see below), whose sum is σ = 8027712. Its totient is φ = 7955592.

The previous prime is 7991639. The next prime is 7991653. The reversal of 7991651 is 1561997.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1561997 = 31 ⋅50387.

It is a cyclic number.

It is not a de Polignac number, because 7991651 - 2¹⁴ = 7975267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7991653) 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, 17696 + ... + 18141.

It is an arithmetic number, because the mean of its divisors is an integer number (2006928).

Almost surely, 2^7991651 is an apocalyptic number.

7991651 is a deficient number, since it is larger than the sum of its proper divisors (36061).

7991651 is a wasteful number, since it uses less digits than its factorization.

7991651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36060.

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

The square root of 7991651 is about 2826.9508308423. The cubic root of 7991651 is about 199.9304007826.

The spelling of 7991651 in words is "seven million, nine hundred ninety-one thousand, six hundred fifty-one".