21001000100101 has 16 divisors (see below), whose sum is σ = 24631868131200. Its totient is φ = 17533411512768.

The previous prime is 21001000100081. The next prime is 21001000100107. The reversal of 21001000100101 is 10100100010012.

It is a cyclic number.

It is not a de Polignac number, because 21001000100101 - 2⁹ = 21001000099589 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (7).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001000100107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 233211310 + ... + 233301343.

It is an arithmetic number, because the mean of its divisors is an integer number (1539491758200).

Almost surely, 2^{21001000100101} is an apocalyptic number.

It is an amenable number.

21001000100101 is a deficient number, since it is larger than the sum of its proper divisors (3630868031099).

21001000100101 is a wasteful number, since it uses less digits than its factorization.

21001000100101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466512828.

The product of its (nonzero) digits is 2, while the sum is 7.

Adding to 21001000100101 its reverse (10100100010012), we get a palindrome (31101100110113).

The spelling of 21001000100101 in words is "twenty-one trillion, one billion, one hundred thousand, one hundred one".