21201222012101 has 4 divisors (see below), whose sum is σ = 21201234873804. Its totient is φ = 21201209150400.

The previous prime is 21201222012079. The next prime is 21201222012107. The reversal of 21201222012101 is 10121022210212.

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 6618553749025 + 14582668263076 = 2572655^2 + 3818726^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201222012101 - 2¹⁸ = 21201221749957 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21201222012101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201222012107) 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, 3518660 + ... + 7401581.

It is an arithmetic number, because the mean of its divisors is an integer number (5300308718451).

Almost surely, 2^{21201222012101} is an apocalyptic number.

It is an amenable number.

21201222012101 is a deficient number, since it is larger than the sum of its proper divisors (12861703).

21201222012101 is a wasteful number, since it uses less digits than its factorization.

21201222012101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12861702.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21201222012101 its reverse (10121022210212), we get a palindrome (31322244222313).

The spelling of 21201222012101 in words is "twenty-one trillion, two hundred one billion, two hundred twenty-two million, twelve thousand, one hundred one".