20644427 has 4 divisors (see below), whose sum is σ = 20677776. Its totient is φ = 20611080.

The previous prime is 20644399. The next prime is 20644447. The reversal of 20644427 is 72444602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 72444602 = 2 ⋅36222301.

It is a cyclic number.

It is not a de Polignac number, because 20644427 - 2¹² = 20640331 is a prime.

It is a super-3 number, since 3×20644427³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20644427.

It is not an unprimeable number, because it can be changed into a prime (20644447) 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, 15728 + ... + 16989.

It is an arithmetic number, because the mean of its divisors is an integer number (5169444).

Almost surely, 2^20644427 is an apocalyptic number.

20644427 is a deficient number, since it is larger than the sum of its proper divisors (33349).

20644427 is an equidigital number, since it uses as much as digits as its factorization.

20644427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33348.

The product of its (nonzero) digits is 10752, while the sum is 29.

The square root of 20644427 is about 4543.6138700378. The cubic root of 20644427 is about 274.3264043082.

The spelling of 20644427 in words is "twenty million, six hundred forty-four thousand, four hundred twenty-seven".