21012100999999 has 4 divisors (see below), whose sum is σ = 21012202770064. Its totient is φ = 21011999229936.

The previous prime is 21012100999993. The next prime is 21012101000081. The reversal of 21012100999999 is 99999900121012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21012100999999 - 2¹⁹ = 21012100475711 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012100999993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50574702 + ... + 50988475.

It is an arithmetic number, because the mean of its divisors is an integer number (5253050692516).

Almost surely, 2^{21012100999999} is an apocalyptic number.

21012100999999 is a deficient number, since it is larger than the sum of its proper divisors (101770065).

21012100999999 is a wasteful number, since it uses less digits than its factorization.

21012100999999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101770064.

The product of its (nonzero) digits is 2125764, while the sum is 61.

The spelling of 21012100999999 in words is "twenty-one trillion, twelve billion, one hundred million, nine hundred ninety-nine thousand, nine hundred ninety-nine".