20644406 has 4 divisors (see below), whose sum is σ = 30966612. Its totient is φ = 10322202.

The previous prime is 20644399. The next prime is 20644447. The reversal of 20644406 is 60444602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60444602 = 2 ⋅30222301.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5161100 + ... + 5161103.

It is an arithmetic number, because the mean of its divisors is an integer number (7741653).

Almost surely, 2^20644406 is an apocalyptic number.

20644406 is a deficient number, since it is larger than the sum of its proper divisors (10322206).

20644406 is a wasteful number, since it uses less digits than its factorization.

20644406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10322205.

The product of its (nonzero) digits is 4608, while the sum is 26.

The square root of 20644406 is about 4543.6115591014. The cubic root of 20644406 is about 274.3263112911.

The spelling of 20644406 in words is "twenty million, six hundred forty-four thousand, four hundred six".