7991644 has 6 divisors (see below), whose sum is σ = 13985384. Its totient is φ = 3995820.

The previous prime is 7991639. The next prime is 7991653. The reversal of 7991644 is 4461997.

It is a happy number.

7991644 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 7991597 and 7991606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 998952 + ... + 998959.

Almost surely, 2^7991644 is an apocalyptic number.

It is an amenable number.

7991644 is a deficient number, since it is larger than the sum of its proper divisors (5993740).

7991644 is a wasteful number, since it uses less digits than its factorization.

7991644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1997915 (or 1997913 counting only the distinct ones).

The product of its digits is 54432, while the sum is 40.

The square root of 7991644 is about 2826.9495927590. The cubic root of 7991644 is about 199.9303424086.

It can be divided in two parts, 799164 and 4, that multiplied together give a triangular number (3196656 = T₂₅₂₈).

The spelling of 7991644 in words is "seven million, nine hundred ninety-one thousand, six hundred forty-four".