20989633 has 16 divisors (see below), whose sum is σ = 24773760. Its totient is φ = 17410176.

The previous prime is 20989627. The next prime is 20989651. The reversal of 20989633 is 33698902.

It is not a de Polignac number, because 20989633 - 2⁵ = 20989601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20989603) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40983 + ... + 41491.

It is an arithmetic number, because the mean of its divisors is an integer number (1548360).

Almost surely, 2^20989633 is an apocalyptic number.

It is an amenable number.

20989633 is a deficient number, since it is larger than the sum of its proper divisors (3784127).

20989633 is a wasteful number, since it uses less digits than its factorization.

20989633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 696.

The product of its (nonzero) digits is 69984, while the sum is 40.

The square root of 20989633 is about 4581.4444228867. Note that the first 4 decimals coincide. The cubic root of 20989633 is about 275.8470105352.

The spelling of 20989633 in words is "twenty million, nine hundred eighty-nine thousand, six hundred thirty-three".