21674388166 has 4 divisors (see below), whose sum is σ = 32511582252. Its totient is φ = 10837194082.

The previous prime is 21674388163. The next prime is 21674388173. The reversal of 21674388166 is 66188347612.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21674388163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5418597040 + ... + 5418597043.

It is an arithmetic number, because the mean of its divisors is an integer number (8127895563).

Almost surely, 2^21674388166 is an apocalyptic number.

21674388166 is a deficient number, since it is larger than the sum of its proper divisors (10837194086).

21674388166 is a wasteful number, since it uses less digits than its factorization.

21674388166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10837194085.

The product of its digits is 2322432, while the sum is 52.

The spelling of 21674388166 in words is "twenty-one billion, six hundred seventy-four million, three hundred eighty-eight thousand, one hundred sixty-six".