21121110191 has 8 divisors (see below), whose sum is σ = 21249244800. Its totient is φ = 20993088600.

The previous prime is 21121110173. The next prime is 21121110209. The reversal of 21121110191 is 19101112112.

It is an interprime number because it is at equal distance from previous prime (21121110173) and next prime (21121110209).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21121110191 - 2²² = 21116915887 is a prime.

It is a super-2 number, since 2×21121110191² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121110161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 362966 + ... + 417116.

It is an arithmetic number, because the mean of its divisors is an integer number (2656155600).

Almost surely, 2^21121110191 is an apocalyptic number.

21121110191 is a deficient number, since it is larger than the sum of its proper divisors (128134609).

21121110191 is a wasteful number, since it uses less digits than its factorization.

21121110191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56509.

The product of its (nonzero) digits is 36, while the sum is 20.

The spelling of 21121110191 in words is "twenty-one billion, one hundred twenty-one million, one hundred ten thousand, one hundred ninety-one".