21015112191 has 16 divisors (see below), whose sum is σ = 28110412800. Its totient is φ = 13965003360.

The previous prime is 21015112163. The next prime is 21015112219. The reversal of 21015112191 is 19121151012.

It is an interprime number because it is at equal distance from previous prime (21015112163) and next prime (21015112219).

It is not a de Polignac number, because 21015112191 - 2¹⁴ = 21015095807 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21015112991) 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, 1561710 + ... + 1575108.

It is an arithmetic number, because the mean of its divisors is an integer number (1756900800).

Almost surely, 2^21015112191 is an apocalyptic number.

21015112191 is a deficient number, since it is larger than the sum of its proper divisors (7095300609).

21015112191 is a wasteful number, since it uses less digits than its factorization.

21015112191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15046.

The product of its (nonzero) digits is 180, while the sum is 24.

The spelling of 21015112191 in words is "twenty-one billion, fifteen million, one hundred twelve thousand, one hundred ninety-one".