20989493 has 12 divisors (see below), whose sum is σ = 24695820. Its totient is φ = 17785152.

The previous prime is 20989483. The next prime is 20989513. The reversal of 20989493 is 39498902.

It can be written as a sum of positive squares in 2 ways, for example, as 9746884 + 11242609 = 3122^2 + 3353^2 .

It is not a de Polignac number, because 20989493 - 2⁴ = 20989477 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20989483) 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, 1955 + ... + 6767.

It is an arithmetic number, because the mean of its divisors is an integer number (2057985).

Almost surely, 2^20989493 is an apocalyptic number.

It is an amenable number.

20989493 is a deficient number, since it is larger than the sum of its proper divisors (3706327).

20989493 is an equidigital number, since it uses as much as digits as its factorization.

20989493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4916 (or 4909 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 44.

The square root of 20989493 is about 4581.4291438371. The cubic root of 20989493 is about 275.8463972378.

The spelling of 20989493 in words is "twenty million, nine hundred eighty-nine thousand, four hundred ninety-three".