21192850871 has 4 divisors (see below), whose sum is σ = 21685707912. Its totient is φ = 20699993832.

The previous prime is 21192850843. The next prime is 21192850873. The reversal of 21192850871 is 17805829112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21192850871 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21192850873) 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, 246428456 + ... + 246428541.

It is an arithmetic number, because the mean of its divisors is an integer number (5421426978).

Almost surely, 2^21192850871 is an apocalyptic number.

21192850871 is a deficient number, since it is larger than the sum of its proper divisors (492857041).

21192850871 is an equidigital number, since it uses as much as digits as its factorization.

21192850871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492857040.

The product of its (nonzero) digits is 80640, while the sum is 44.

The spelling of 21192850871 in words is "twenty-one billion, one hundred ninety-two million, eight hundred fifty thousand, eight hundred seventy-one".