20820823 has 4 divisors (see below), whose sum is σ = 20856528. Its totient is φ = 20785120.

The previous prime is 20820817. The next prime is 20820829. The reversal of 20820823 is 32802802.

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

It is an interprime number because it is at equal distance from previous prime (20820817) and next prime (20820829).

It is a cyclic number.

It is not a de Polignac number, because 20820823 - 2⁹ = 20820311 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 (20820829) 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, 16963 + ... + 18148.

It is an arithmetic number, because the mean of its divisors is an integer number (5214132).

Almost surely, 2^20820823 is an apocalyptic number.

20820823 is a deficient number, since it is larger than the sum of its proper divisors (35705).

20820823 is an equidigital number, since it uses as much as digits as its factorization.

20820823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35704.

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 20820823 is about 4562.9840017252. The cubic root of 20820823 is about 275.1055154322.

The spelling of 20820823 in words is "twenty million, eight hundred twenty thousand, eight hundred twenty-three".