20641623 has 4 divisors (see below), whose sum is σ = 27522168. Its totient is φ = 13761080.

The previous prime is 20641609. The next prime is 20641627. The reversal of 20641623 is 32614602.

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 20641623 - 2⁶ = 20641559 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20641593 and 20641602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20641627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3440268 + ... + 3440273.

It is an arithmetic number, because the mean of its divisors is an integer number (6880542).

Almost surely, 2^20641623 is an apocalyptic number.

20641623 is a deficient number, since it is larger than the sum of its proper divisors (6880545).

20641623 is an equidigital number, since it uses as much as digits as its factorization.

20641623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6880544.

The product of its (nonzero) digits is 1728, while the sum is 24.

The square root of 20641623 is about 4543.3052946066. The cubic root of 20641623 is about 274.3139837477.

The spelling of 20641623 in words is "twenty million, six hundred forty-one thousand, six hundred twenty-three".