21660338267 has 4 divisors (see below), whose sum is σ = 22121196576. Its totient is φ = 21199479960.

The previous prime is 21660338261. The next prime is 21660338269. The reversal of 21660338267 is 76283306612.

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

It is a cyclic number.

It is not a de Polignac number, because 21660338267 - 2¹⁰ = 21660337243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21660338261) 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, 230429084 + ... + 230429177.

It is an arithmetic number, because the mean of its divisors is an integer number (5530299144).

Almost surely, 2^21660338267 is an apocalyptic number.

21660338267 is a deficient number, since it is larger than the sum of its proper divisors (460858309).

21660338267 is an equidigital number, since it uses as much as digits as its factorization.

21660338267 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460858308.

The product of its (nonzero) digits is 435456, while the sum is 44.

The spelling of 21660338267 in words is "twenty-one billion, six hundred sixty million, three hundred thirty-eight thousand, two hundred sixty-seven".