100000000021 has 4 divisors (see below), whose sum is σ = 100003015692. Its totient is φ = 99996984352.

The previous prime is 100000000019. The next prime is 100000000057. The reversal of 100000000021 is 120000000001.

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 59907947121 + 40092052900 = 244761^2 + 200230^2 .

It is a cyclic number.

It is not a de Polignac number, because 100000000021 - 2¹ = 100000000019 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 (100000000091) 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, 1457536 + ... + 1524601.

It is an arithmetic number, because the mean of its divisors is an integer number (25000753923).

Almost surely, 2^100000000021 is an apocalyptic number.

It is an amenable number.

100000000021 is a deficient number, since it is larger than the sum of its proper divisors (3015671).

100000000021 is an equidigital number, since it uses as much as digits as its factorization.

100000000021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3015670.

The product of its (nonzero) digits is 2, while the sum is 4.

Adding to 100000000021 its reverse (120000000001), we get a palindrome (220000000022).

The spelling of 100000000021 in words is "one hundred billion, twenty-one", and thus it is an aban number.