21210100101 has 16 divisors (see below), whose sum is σ = 31424833920. Its totient is φ = 14138958240.

The previous prime is 21210100081. The next prime is 21210100111. The reversal of 21210100101 is 10100101212.

It is a happy number.

It is not a de Polignac number, because 21210100101 - 2⁷ = 21210099973 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210100111) 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, 465336 + ... + 508878.

It is an arithmetic number, because the mean of its divisors is an integer number (1964052120).

Almost surely, 2^21210100101 is an apocalyptic number.

It is an amenable number.

21210100101 is a deficient number, since it is larger than the sum of its proper divisors (10214733819).

21210100101 is a wasteful number, since it uses less digits than its factorization.

21210100101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61593 (or 61587 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21210100101 its reverse (10100101212), we get a palindrome (31310201313).

It can be divided in two parts, 212 and 10100101, that multiplied together give a palindrome (2141221412).

The spelling of 21210100101 in words is "twenty-one billion, two hundred ten million, one hundred thousand, one hundred one".