21101999999999 has 4 divisors (see below), whose sum is σ = 22343294117664. Its totient is φ = 19860705882336.

The previous prime is 21101999999959. The next prime is 21102000000043. The reversal of 21101999999999 is 99999999910112.

It is a happy number.

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

It is a de Polignac number, because none of the positive numbers 2^k-21101999999999 is a prime.

It is a Duffinian number.

21101999999999 is a modest number, since divided by 9999999 gives 2110199 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 21101999999999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101999999939) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 620647058807 + ... + 620647058840.

It is an arithmetic number, because the mean of its divisors is an integer number (5585823529416).

Almost surely, 2^{21101999999999} is an apocalyptic number.

21101999999999 is a deficient number, since it is larger than the sum of its proper divisors (1241294117665).

21101999999999 is a wasteful number, since it uses less digits than its factorization.

21101999999999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1241294117664.

The product of its (nonzero) digits is 774840978, while the sum is 86.

The spelling of 21101999999999 in words is "twenty-one trillion, one hundred one billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine".