20422643 has 4 divisors (see below), whose sum is σ = 21310608. Its totient is φ = 19534680.

The previous prime is 20422637. The next prime is 20422651. The reversal of 20422643 is 34622402.

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 20422643 - 2⁶ = 20422579 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 887941 = 20422643 / (2 + 0 + 4 + 2 + 2 + 6 + 4 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20422613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 443948 + ... + 443993.

It is an arithmetic number, because the mean of its divisors is an integer number (5327652).

Almost surely, 2^20422643 is an apocalyptic number.

20422643 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

20422643 is a deficient number, since it is larger than the sum of its proper divisors (887965).

20422643 is an equidigital number, since it uses as much as digits as its factorization.

20422643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 887964.

The product of its (nonzero) digits is 2304, while the sum is 23.

The square root of 20422643 is about 4519.1418433149. The cubic root of 20422643 is about 273.3404983580.

The spelling of 20422643 in words is "twenty million, four hundred twenty-two thousand, six hundred forty-three".