20168210921 has 8 divisors (see below), whose sum is σ = 20874070920. Its totient is φ = 19463044608.

The previous prime is 20168210917. The next prime is 20168210989. The reversal of 20168210921 is 12901286102.

It can be written as a sum of positive squares in 4 ways, for example, as 5117828521 + 15050382400 = 71539^2 + 122680^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20168210921 - 2² = 20168210917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20168290921) 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 7 ways as a sum of consecutive naturals, for example, 113906 + ... + 230891.

It is an arithmetic number, because the mean of its divisors is an integer number (2609258865).

Almost surely, 2^20168210921 is an apocalyptic number.

It is an amenable number.

20168210921 is a deficient number, since it is larger than the sum of its proper divisors (705859999).

20168210921 is a wasteful number, since it uses less digits than its factorization.

20168210921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 346843.

The product of its (nonzero) digits is 3456, while the sum is 32.

The spelling of 20168210921 in words is "twenty billion, one hundred sixty-eight million, two hundred ten thousand, nine hundred twenty-one".