100202020021 has 4 divisors (see below), whose sum is σ = 100419378444. Its totient is φ = 99984661600.

The previous prime is 100202019893. The next prime is 100202020063. The reversal of 100202020021 is 120020202001.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120020202001 = 7 ⋅17145743143.

It can be written as a sum of positive squares in 2 ways, for example, as 65146947121 + 35055072900 = 255239^2 + 187230^2 .

It is a cyclic number.

It is not a de Polignac number, because 100202020021 - 2⁷ = 100202019893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100202020081) 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 3 ways as a sum of consecutive naturals, for example, 108678520 + ... + 108679441.

It is an arithmetic number, because the mean of its divisors is an integer number (25104844611).

Almost surely, 2^100202020021 is an apocalyptic number.

It is an amenable number.

100202020021 is a deficient number, since it is larger than the sum of its proper divisors (217358423).

100202020021 is an equidigital number, since it uses as much as digits as its factorization.

100202020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217358422.

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 100202020021 its reverse (120020202001), we get a palindrome (220222222022).

The spelling of 100202020021 in words is "one hundred billion, two hundred two million, twenty thousand, twenty-one".