21021106697099 has 4 divisors (see below), whose sum is σ = 21071276403240. Its totient is φ = 20970936990960.

The previous prime is 21021106697093. The next prime is 21021106697111. The reversal of 21021106697099 is 99079660112012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21021106697099 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21021106697099.

It is not an unprimeable number, because it can be changed into a prime (21021106697093) 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, 25084852442 + ... + 25084853279.

It is an arithmetic number, because the mean of its divisors is an integer number (5267819100810).

Almost surely, 2^{21021106697099} is an apocalyptic number.

21021106697099 is a deficient number, since it is larger than the sum of its proper divisors (50169706141).

21021106697099 is an equidigital number, since it uses as much as digits as its factorization.

21021106697099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50169706140.

The product of its (nonzero) digits is 734832, while the sum is 53.

The spelling of 21021106697099 in words is "twenty-one trillion, twenty-one billion, one hundred six million, six hundred ninety-seven thousand, ninety-nine".