21210102100021 has 16 divisors (see below), whose sum is σ = 22502875780800. Its totient is φ = 19935407000448.

The previous prime is 21210102100007. The next prime is 21210102100051. The reversal of 21210102100021 is 12000120101212.

It is not a de Polignac number, because 21210102100021 - 2²⁹ = 21209565229109 is a prime.

It is a super-3 number, since 3×21210102100021³ (a number of 41 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21210102099974 and 21210102100010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210102100001) 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, 4255906 + ... + 7780291.

It is an arithmetic number, because the mean of its divisors is an integer number (1406429736300).

Almost surely, 2^{21210102100021} is an apocalyptic number.

It is an amenable number.

21210102100021 is a deficient number, since it is larger than the sum of its proper divisors (1292773680779).

21210102100021 is a wasteful number, since it uses less digits than its factorization.

21210102100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12036948.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21210102100021 its reverse (12000120101212), we get a palindrome (33210222201233).

The spelling of 21210102100021 in words is "twenty-one trillion, two hundred ten billion, one hundred two million, one hundred thousand, twenty-one".