20017972891 has 32 divisors (see below), whose sum is σ = 24161792000. Its totient is φ = 16560573120.

The previous prime is 20017972831. The next prime is 20017972901. The reversal of 20017972891 is 19827971002.

It is not a de Polignac number, because 20017972891 - 2¹³ = 20017964699 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20017972801) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4346596 + ... + 4351198.

It is an arithmetic number, because the mean of its divisors is an integer number (755056000).

Almost surely, 2^20017972891 is an apocalyptic number.

20017972891 is a deficient number, since it is larger than the sum of its proper divisors (4143819109).

20017972891 is an equidigital number, since it uses as much as digits as its factorization.

20017972891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5064 (or 5050 counting only the distinct ones).

The product of its (nonzero) digits is 127008, while the sum is 46.

The spelling of 20017972891 in words is "twenty billion, seventeen million, nine hundred seventy-two thousand, eight hundred ninety-one".