20644423 has 4 divisors (see below), whose sum is σ = 20654368. Its totient is φ = 20634480.

The previous prime is 20644399. The next prime is 20644447. The reversal of 20644423 is 32444602.

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.

It is an interprime number because it is at equal distance from previous prime (20644399) and next prime (20644447).

It is a cyclic number.

It is not a de Polignac number, because 20644423 - 2⁵ = 20644391 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 (20644453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 543 + ... + 6448.

It is an arithmetic number, because the mean of its divisors is an integer number (5163592).

Almost surely, 2^20644423 is an apocalyptic number.

20644423 is a deficient number, since it is larger than the sum of its proper divisors (9945).

20644423 is an equidigital number, since it uses as much as digits as its factorization.

20644423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9944.

The product of its (nonzero) digits is 4608, while the sum is 25.

The square root of 20644423 is about 4543.6134298595. The cubic root of 20644423 is about 274.3263865907.

The spelling of 20644423 in words is "twenty million, six hundred forty-four thousand, four hundred twenty-three".