20604989 has 4 divisors (see below), whose sum is σ = 20614620. Its totient is φ = 20595360.

The previous prime is 20604973. The next prime is 20605019. The reversal of 20604989 is 98940602.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 98940602 = 2 ⋅49470301.

It can be written as a sum of positive squares in 2 ways, for example, as 8584900 + 12020089 = 2930^2 + 3467^2 .

It is a cyclic number.

It is not a de Polignac number, because 20604989 - 2⁴ = 20604973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20604959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2 + ... + 6419.

It is an arithmetic number, because the mean of its divisors is an integer number (5153655).

Almost surely, 2^20604989 is an apocalyptic number.

It is an amenable number.

20604989 is a deficient number, since it is larger than the sum of its proper divisors (9631).

20604989 is an equidigital number, since it uses as much as digits as its factorization.

20604989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9630.

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 20604989 is about 4539.2718579085. The cubic root of 20604989 is about 274.1516068302.

The spelling of 20604989 in words is "twenty million, six hundred four thousand, nine hundred eighty-nine".