20840823 has 6 divisors (see below), whose sum is σ = 30103424. Its totient is φ = 13893876.

The previous prime is 20840789. The next prime is 20840837. The reversal of 20840823 is 32804802.

It is not a de Polignac number, because 20840823 - 2⁹ = 20840311 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 (20840873) 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 5 ways as a sum of consecutive naturals, for example, 1157815 + ... + 1157832.

Almost surely, 2^20840823 is an apocalyptic number.

20840823 is a deficient number, since it is larger than the sum of its proper divisors (9262601).

20840823 is a wasteful number, since it uses less digits than its factorization.

20840823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2315653 (or 2315650 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 20840823 is about 4565.1750240270. The cubic root of 20840823 is about 275.1935739032.

The spelling of 20840823 in words is "twenty million, eight hundred forty thousand, eight hundred twenty-three".