7997921 has 8 divisors (see below), whose sum is σ = 8127840. Its totient is φ = 7869312.

The previous prime is 7997903. The next prime is 7997933. The reversal of 7997921 is 1297997.

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 7997921 - 2¹⁴ = 7981537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7997971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22481 + ... + 22833.

It is an arithmetic number, because the mean of its divisors is an integer number (1015980).

Almost surely, 2^7997921 is an apocalyptic number.

It is an amenable number.

7997921 is a deficient number, since it is larger than the sum of its proper divisors (129919).

7997921 is a wasteful number, since it uses less digits than its factorization.

7997921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 655.

The product of its digits is 71442, while the sum is 44.

The square root of 7997921 is about 2828.0595821163. The cubic root of 7997921 is about 199.9826734990.

The spelling of 7997921 in words is "seven million, nine hundred ninety-seven thousand, nine hundred twenty-one".