21187112473 has 4 divisors (see below), whose sum is σ = 21348846288. Its totient is φ = 21025378660.

The previous prime is 21187112449. The next prime is 21187112483. The reversal of 21187112473 is 37421178112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21187112473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21187112483) 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, 80866711 + ... + 80866972.

It is an arithmetic number, because the mean of its divisors is an integer number (5337211572).

Almost surely, 2^21187112473 is an apocalyptic number.

It is an amenable number.

21187112473 is a deficient number, since it is larger than the sum of its proper divisors (161733815).

21187112473 is a wasteful number, since it uses less digits than its factorization.

21187112473 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161733814.

The product of its digits is 18816, while the sum is 37.

The spelling of 21187112473 in words is "twenty-one billion, one hundred eighty-seven million, one hundred twelve thousand, four hundred seventy-three".