21010211999 has 4 divisors (see below), whose sum is σ = 24011670864. Its totient is φ = 18008753136.

The previous prime is 21010211993. The next prime is 21010212007. The reversal of 21010211999 is 99911201012.

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 21010211999 - 2²⁸ = 20741776543 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 (21010211993) 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, 1500729422 + ... + 1500729435.

It is an arithmetic number, because the mean of its divisors is an integer number (6002917716).

Almost surely, 2^21010211999 is an apocalyptic number.

21010211999 is a deficient number, since it is larger than the sum of its proper divisors (3001458865).

21010211999 is an equidigital number, since it uses as much as digits as its factorization.

21010211999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3001458864.

The product of its (nonzero) digits is 2916, while the sum is 35.

The spelling of 21010211999 in words is "twenty-one billion, ten million, two hundred eleven thousand, nine hundred ninety-nine".