21101211102021 has 4 divisors (see below), whose sum is σ = 28134948136032. Its totient is φ = 14067474068012.

The previous prime is 21101211101989. The next prime is 21101211102029. The reversal of 21101211102021 is 12020111210112.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 21101211102021 - 2⁵ = 21101211101989 is a prime.

It is a super-2 number, since 2×21101211102021² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101211102029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3516868517001 + ... + 3516868517006.

It is an arithmetic number, because the mean of its divisors is an integer number (7033737034008).

Almost surely, 2^{21101211102021} is an apocalyptic number.

It is an amenable number.

21101211102021 is a deficient number, since it is larger than the sum of its proper divisors (7033737034011).

21101211102021 is an equidigital number, since it uses as much as digits as its factorization.

21101211102021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7033737034010.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21101211102021 its reverse (12020111210112), we get a palindrome (33121322312133).

The spelling of 21101211102021 in words is "twenty-one trillion, one hundred one billion, two hundred eleven million, one hundred two thousand, twenty-one".