20321020291891 has 8 divisors (see below), whose sum is σ = 22177688523264. Its totient is φ = 18465902518920.

The previous prime is 20321020291757. The next prime is 20321020291903. The reversal of 20321020291891 is 19819202012302.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20321020291891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20321080291891) 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, 387587191 + ... + 387639616.

It is an arithmetic number, because the mean of its divisors is an integer number (2772211065408).

Almost surely, 2^{20321020291891} is an apocalyptic number.

20321020291891 is a deficient number, since it is larger than the sum of its proper divisors (1856668231373).

20321020291891 is a wasteful number, since it uses less digits than its factorization.

20321020291891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 775229201.

The product of its (nonzero) digits is 31104, while the sum is 40.

The spelling of 20321020291891 in words is "twenty trillion, three hundred twenty-one billion, twenty million, two hundred ninety-one thousand, eight hundred ninety-one".