21366008165 has 8 divisors (see below), whose sum is σ = 25640720160. Its totient is φ = 17091799632.

The previous prime is 21366008159. The next prime is 21366008177. The reversal of 21366008165 is 56180066312.

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 21366008165 - 2⁴ = 21366008149 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25175 + ... + 208244.

It is an arithmetic number, because the mean of its divisors is an integer number (3205090020).

Almost surely, 2^21366008165 is an apocalyptic number.

It is an amenable number.

21366008165 is a deficient number, since it is larger than the sum of its proper divisors (4274711995).

21366008165 is a wasteful number, since it uses less digits than its factorization.

21366008165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251731.

The product of its (nonzero) digits is 51840, while the sum is 38.

The spelling of 21366008165 in words is "twenty-one billion, three hundred sixty-six million, eight thousand, one hundred sixty-five".