21102100101 has 8 divisors (see below), whose sum is σ = 31262370560. Its totient is φ = 14068066716.

The previous prime is 21102100081. The next prime is 21102100109. The reversal of 21102100101 is 10100120112.

It is a happy number.

It is not a de Polignac number, because 21102100101 - 2⁹ = 21102099589 is a prime.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102100109) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 390779605 + ... + 390779658.

It is an arithmetic number, because the mean of its divisors is an integer number (3907796320).

Almost surely, 2^21102100101 is an apocalyptic number.

It is an amenable number.

21102100101 is a deficient number, since it is larger than the sum of its proper divisors (10160270459).

21102100101 is an equidigital number, since it uses as much as digits as its factorization.

21102100101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 781559272 (or 781559266 counting only the distinct ones).

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

Adding to 21102100101 its reverse (10100120112), we get a palindrome (31202220213).

The spelling of 21102100101 in words is "twenty-one billion, one hundred two million, one hundred thousand, one hundred one".