21211222101021 has 6 divisors (see below), whose sum is σ = 30638431923710. Its totient is φ = 14140814734008.

The previous prime is 21211222101019. The next prime is 21211222101049. The reversal of 21211222101021 is 12010122211212.

It can be written as a sum of positive squares in only one way, i.e., 17569762056900 + 3641460044121 = 4191630^2 + 1908261^2 .

It is not a de Polignac number, because 21211222101021 - 2¹ = 21211222101019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211222100985 and 21211222101003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211222101071) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1178401227826 + ... + 1178401227843.

Almost surely, 2^{21211222101021} is an apocalyptic number.

It is an amenable number.

21211222101021 is a deficient number, since it is larger than the sum of its proper divisors (9427209822689).

21211222101021 is a wasteful number, since it uses less digits than its factorization.

21211222101021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2356802455675 (or 2356802455672 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21211222101021 its reverse (12010122211212), we get a palindrome (33221344312233).

The spelling of 21211222101021 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty-two million, one hundred one thousand, twenty-one".