21111500211 has 4 divisors (see below), whose sum is σ = 28148666952. Its totient is φ = 14074333472.

The previous prime is 21111500197. The next prime is 21111500213. The reversal of 21111500211 is 11200511112.

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 21111500211 - 2⁶ = 21111500147 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21111500213) 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, 3518583366 + ... + 3518583371.

It is an arithmetic number, because the mean of its divisors is an integer number (7037166738).

Almost surely, 2^21111500211 is an apocalyptic number.

21111500211 is a deficient number, since it is larger than the sum of its proper divisors (7037166741).

21111500211 is an equidigital number, since it uses as much as digits as its factorization.

21111500211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7037166740.

The product of its (nonzero) digits is 20, while the sum is 15.

The spelling of 21111500211 in words is "twenty-one billion, one hundred eleven million, five hundred thousand, two hundred eleven".