21201100001021 has 4 divisors (see below), whose sum is σ = 21201110136000. Its totient is φ = 21201089866044.

The previous prime is 21201100000999. The next prime is 21201100001023. The reversal of 21201100001021 is 12010000110212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21201100001021 - 2¹⁴ = 21201099984637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21201100000993 and 21201100001011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201100001023) 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, 640571 + ... + 6543128.

It is an arithmetic number, because the mean of its divisors is an integer number (5300277534000).

Almost surely, 2^{21201100001021} is an apocalyptic number.

It is an amenable number.

21201100001021 is a deficient number, since it is larger than the sum of its proper divisors (10134979).

21201100001021 is an equidigital number, since it uses as much as digits as its factorization.

21201100001021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10134978.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21201100001021 its reverse (12010000110212), we get a palindrome (33211100111233).

The spelling of 21201100001021 in words is "twenty-one trillion, two hundred one billion, one hundred million, one thousand, twenty-one".