20644463 has 4 divisors (see below), whose sum is σ = 23593680. Its totient is φ = 17695248.

The previous prime is 20644453. The next prime is 20644471. The reversal of 20644463 is 36444602.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20644463 - 2⁴ = 20644447 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 (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1474598 + ... + 1474611.

It is an arithmetic number, because the mean of its divisors is an integer number (5898420).

Almost surely, 2^20644463 is an apocalyptic number.

20644463 is a deficient number, since it is larger than the sum of its proper divisors (2949217).

20644463 is an equidigital number, since it uses as much as digits as its factorization.

20644463 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2949216.

The product of its (nonzero) digits is 13824, while the sum is 29.

The square root of 20644463 is about 4543.6178316403. The cubic root of 20644463 is about 274.3265637660.

The spelling of 20644463 in words is "twenty million, six hundred forty-four thousand, four hundred sixty-three".