21000020012201 has 4 divisors (see below), whose sum is σ = 21000039918804. Its totient is φ = 21000000105600.

The previous prime is 21000020012197. The next prime is 21000020012227. The reversal of 21000020012201 is 10221002000012.

It is a happy number.

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 5786314786576 + 15213705225625 = 2405476^2 + 3900475^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000020012201 - 2² = 21000020012197 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21000020012701) 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, 8276780 + ... + 10512141.

It is an arithmetic number, because the mean of its divisors is an integer number (5250009979701).

Almost surely, 2^{21000020012201} is an apocalyptic number.

It is an amenable number.

21000020012201 is a deficient number, since it is larger than the sum of its proper divisors (19906603).

21000020012201 is a wasteful number, since it uses less digits than its factorization.

21000020012201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19906602.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21000020012201 its reverse (10221002000012), we get a palindrome (31221022012213).

The spelling of 21000020012201 in words is "twenty-one trillion, twenty million, twelve thousand, two hundred one".