100012020021 has 6 divisors (see below), whose sum is σ = 144461806710. Its totient is φ = 66674680008.

The previous prime is 100012020011. The next prime is 100012020037. The reversal of 100012020021 is 120020210001.

It can be written as a sum of positive squares in only one way, i.e., 72314739396 + 27697280625 = 268914^2 + 166425^2 .

It is not a de Polignac number, because 100012020021 - 2²⁵ = 99978465589 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 11112446669 = 100012020021 / (1 + 0 + 0 + 0 + 1 + 2 + 0 + 2 + 0 + 0 + 2 + 1).

It is a junction number, because it is equal to n+sod(n) for n = 100012019985 and 100012020012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100012020011) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5556223326 + ... + 5556223343.

It is an arithmetic number, because the mean of its divisors is an integer number (24076967785).

Almost surely, 2^100012020021 is an apocalyptic number.

It is an amenable number.

100012020021 is a deficient number, since it is larger than the sum of its proper divisors (44449786689).

100012020021 is a wasteful number, since it uses less digits than its factorization.

100012020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11112446675 (or 11112446672 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 100012020021 its reverse (120020210001), we get a palindrome (220032230022).

The spelling of 100012020021 in words is "one hundred billion, twelve million, twenty thousand, twenty-one".