7998921 has 12 divisors (see below), whose sum is σ = 13204672. Its totient is φ = 4570776.

The previous prime is 7998863. The next prime is 7998937. The reversal of 7998921 is 1298997.

7998921 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 7998921 - 2⁹ = 7998409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7998941) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 63421 + ... + 63546.

Almost surely, 2^7998921 is an apocalyptic number.

It is an amenable number.

7998921 is a deficient number, since it is larger than the sum of its proper divisors (5205751).

7998921 is a wasteful number, since it uses less digits than its factorization.

7998921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126980 (or 126977 counting only the distinct ones).

The product of its digits is 81648, while the sum is 45.

The square root of 7998921 is about 2828.2363762599. The cubic root of 7998921 is about 199.9910079291.

The spelling of 7998921 in words is "seven million, nine hundred ninety-eight thousand, nine hundred twenty-one".