20999791923 has 8 divisors (see below), whose sum is σ = 30545151936. Its totient is φ = 12727146600.

The previous prime is 20999791889. The next prime is 20999791937. The reversal of 20999791923 is 32919799902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20999791923 - 2⁹ = 20999791411 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20999791123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 318178633 + ... + 318178698.

It is an arithmetic number, because the mean of its divisors is an integer number (3818143992).

Almost surely, 2^20999791923 is an apocalyptic number.

20999791923 is a deficient number, since it is larger than the sum of its proper divisors (9545360013).

20999791923 is a wasteful number, since it uses less digits than its factorization.

20999791923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 636357345.

The product of its (nonzero) digits is 4960116, while the sum is 60.

The spelling of 20999791923 in words is "twenty billion, nine hundred ninety-nine million, seven hundred ninety-one thousand, nine hundred twenty-three".