8991021 has 8 divisors (see below), whose sum is σ = 12910240. Its totient is φ = 5532912.

The previous prime is 8991007. The next prime is 8991029. The reversal of 8991021 is 1201998.

8991021 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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

It is a de Polignac number, because none of the positive numbers 2^k-8991021 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 8991021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8991029) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 115231 + ... + 115308.

It is an arithmetic number, because the mean of its divisors is an integer number (1613780).

Almost surely, 2^8991021 is an apocalyptic number.

It is an amenable number.

8991021 is a deficient number, since it is larger than the sum of its proper divisors (3919219).

8991021 is a wasteful number, since it uses less digits than its factorization.

8991021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230555.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 8991021 is about 2998.5031265617. The cubic root of 8991021 is about 207.9391849450.

The spelling of 8991021 in words is "eight million, nine hundred ninety-one thousand, twenty-one".