20201000000021 has 16 divisors (see below), whose sum is σ = 21776137494528. Its totient is φ = 18684897620400.

The previous prime is 20201000000017. The next prime is 20201000000039. The reversal of 20201000000021 is 12000000010202.

It is a cyclic number.

It is not a de Polignac number, because 20201000000021 - 2² = 20201000000017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20200999999945 and 20201000000008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20201000000011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10052561 + ... + 11893526.

It is an arithmetic number, because the mean of its divisors is an integer number (1361008593408).

Almost surely, 2^{20201000000021} is an apocalyptic number.

It is an amenable number.

20201000000021 is a deficient number, since it is larger than the sum of its proper divisors (1575137494507).

20201000000021 is a wasteful number, since it uses less digits than its factorization.

20201000000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21947432.

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

Adding to 20201000000021 its reverse (12000000010202), we get a palindrome (32201000010223).

The spelling of 20201000000021 in words is "twenty trillion, two hundred one billion, twenty-one", and thus it is an aban number.