20993798947 has 16 divisors (see below), whose sum is σ = 23163770880. Its totient is φ = 18868640800.

The previous prime is 20993798897. The next prime is 20993798977. The reversal of 20993798947 is 74989739902.

It is a cyclic number.

It is not a de Polignac number, because 20993798947 - 2¹⁵ = 20993766179 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20993798977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 309822 + ... + 371452.

It is an arithmetic number, because the mean of its divisors is an integer number (1447735680).

Almost surely, 2^20993798947 is an apocalyptic number.

20993798947 is a deficient number, since it is larger than the sum of its proper divisors (2169971933).

20993798947 is a wasteful number, since it uses less digits than its factorization.

20993798947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61994.

The product of its (nonzero) digits is 61725888, while the sum is 67.

The spelling of 20993798947 in words is "twenty billion, nine hundred ninety-three million, seven hundred ninety-eight thousand, nine hundred forty-seven".