21111101191 has 16 divisors (see below), whose sum is σ = 22811891200. Its totient is φ = 19476220608.

The previous prime is 21111101189. The next prime is 21111101197. The reversal of 21111101191 is 19110111112.

It is a cyclic number.

It is not a de Polignac number, because 21111101191 - 2¹ = 21111101189 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111101197) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13240 + ... + 205906.

It is an arithmetic number, because the mean of its divisors is an integer number (1425743200).

Almost surely, 2^21111101191 is an apocalyptic number.

21111101191 is a deficient number, since it is larger than the sum of its proper divisors (1700790009).

21111101191 is a wasteful number, since it uses less digits than its factorization.

21111101191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192838.

The product of its (nonzero) digits is 18, while the sum is 19.

The spelling of 21111101191 in words is "twenty-one billion, one hundred eleven million, one hundred one thousand, one hundred ninety-one".