20823920491 has 4 divisors (see below), whose sum is σ = 22717004184. Its totient is φ = 18930836800.

The previous prime is 20823920489. The next prime is 20823920581. The reversal of 20823920491 is 19402932802.

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 20823920491 - 2¹ = 20823920489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20823920401) 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, 946541830 + ... + 946541851.

It is an arithmetic number, because the mean of its divisors is an integer number (5679251046).

Almost surely, 2^20823920491 is an apocalyptic number.

20823920491 is a deficient number, since it is larger than the sum of its proper divisors (1893083693).

20823920491 is a wasteful number, since it uses less digits than its factorization.

20823920491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1893083692.

The product of its (nonzero) digits is 62208, while the sum is 40.

The spelling of 20823920491 in words is "twenty billion, eight hundred twenty-three million, nine hundred twenty thousand, four hundred ninety-one".