20010109921 has 4 divisors (see below), whose sum is σ = 20216399812. Its totient is φ = 19803820032.

The previous prime is 20010109907. The next prime is 20010109943. The reversal of 20010109921 is 12990101002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4908403600 + 15101706321 = 70060^2 + 122889^2 .

It is a cyclic number.

It is not a de Polignac number, because 20010109921 - 2⁷ = 20010109793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20010109991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103144800 + ... + 103144993.

It is an arithmetic number, because the mean of its divisors is an integer number (5054099953).

Almost surely, 2^20010109921 is an apocalyptic number.

It is an amenable number.

20010109921 is a deficient number, since it is larger than the sum of its proper divisors (206289891).

20010109921 is an equidigital number, since it uses as much as digits as its factorization.

20010109921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206289890.

The product of its (nonzero) digits is 324, while the sum is 25.

The spelling of 20010109921 in words is "twenty billion, ten million, one hundred nine thousand, nine hundred twenty-one".