21201011220021 has 16 divisors (see below), whose sum is σ = 28362028681728. Its totient is φ = 14087070835200.

The previous prime is 21201011219989. The next prime is 21201011220083. The reversal of 21201011220021 is 12002211010212.

It is not a de Polignac number, because 21201011220021 - 2⁵ = 21201011219989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201011220421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7568485 + ... + 9984186.

It is an arithmetic number, because the mean of its divisors is an integer number (1772626792608).

Almost surely, 2^{21201011220021} is an apocalyptic number.

It is an amenable number.

21201011220021 is a deficient number, since it is larger than the sum of its proper divisors (7161017461707).

21201011220021 is a wasteful number, since it uses less digits than its factorization.

21201011220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17554012.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21201011220021 its reverse (12002211010212), we get a palindrome (33203222230233).

The spelling of 21201011220021 in words is "twenty-one trillion, two hundred one billion, eleven million, two hundred twenty thousand, twenty-one".