20012121100021 has 8 divisors (see below), whose sum is σ = 20014451652888. Its totient is φ = 20009790720000.

The previous prime is 20012121099979. The next prime is 20012121100061. The reversal of 20012121100021 is 12000112121002.

It can be written as a sum of positive squares in 4 ways, for example, as 2551172423121 + 17460948676900 = 1597239^2 + 4178630^2 .

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 20012121100021 - 2³⁵ = 19977761361653 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20012121099974 and 20012121100010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20012121100061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 463211221 + ... + 463254421.

It is an arithmetic number, because the mean of its divisors is an integer number (2501806456611).

Almost surely, 2^{20012121100021} is an apocalyptic number.

It is an amenable number.

20012121100021 is a deficient number, since it is larger than the sum of its proper divisors (2330552867).

20012121100021 is a wasteful number, since it uses less digits than its factorization.

20012121100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86423.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 20012121100021 its reverse (12000112121002), we get a palindrome (32012233221023).

The spelling of 20012121100021 in words is "twenty trillion, twelve billion, one hundred twenty-one million, one hundred thousand, twenty-one".