7991945 has 8 divisors (see below), whose sum is σ = 10328136. Its totient is φ = 5901696.

The previous prime is 7991941. The next prime is 7991947. The reversal of 7991945 is 5491997.

It can be written as a sum of positive squares in 4 ways, for example, as 1190281 + 6801664 = 1091^2 + 2608^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 7991945 - 2² = 7991941 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 7991896 and 7991905.

It is not an unprimeable number, because it can be changed into a prime (7991941) 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 7 ways as a sum of consecutive naturals, for example, 61412 + ... + 61541.

It is an arithmetic number, because the mean of its divisors is an integer number (1291017).

Almost surely, 2^7991945 is an apocalyptic number.

It is an amenable number.

7991945 is a deficient number, since it is larger than the sum of its proper divisors (2336191).

7991945 is a wasteful number, since it uses less digits than its factorization.

7991945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122971.

The product of its digits is 102060, while the sum is 44.

The square root of 7991945 is about 2827.0028298536. The cubic root of 7991945 is about 199.9328524586.

It can be divided in two parts, 799 and 1945, that added together give a cube (2744 = 14³).

The spelling of 7991945 in words is "seven million, nine hundred ninety-one thousand, nine hundred forty-five".