8999921 has 4 divisors (see below), whose sum is σ = 10285632. Its totient is φ = 7714212.

The previous prime is 8999899. The next prime is 8999927. The reversal of 8999921 is 1299998.

8999921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 8999921 - 2¹⁴ = 8983537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8999927) 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, 642845 + ... + 642858.

It is an arithmetic number, because the mean of its divisors is an integer number (2571408).

Almost surely, 2^8999921 is an apocalyptic number.

It is an amenable number.

8999921 is a deficient number, since it is larger than the sum of its proper divisors (1285711).

8999921 is a wasteful number, since it uses less digits than its factorization.

8999921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1285710.

The product of its digits is 104976, while the sum is 47.

The square root of 8999921 is about 2999.9868333044. The cubic root of 8999921 is about 208.0077736863.

The spelling of 8999921 in words is "eight million, nine hundred ninety-nine thousand, nine hundred twenty-one".