21666563467 has 8 divisors (see below), whose sum is σ = 22303201536. Its totient is φ = 21035960232.

The previous prime is 21666563453. The next prime is 21666563483. The reversal of 21666563467 is 76436566612.

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 21666563467 - 2¹¹ = 21666561419 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21666561467) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1501423 + ... + 1515784.

It is an arithmetic number, because the mean of its divisors is an integer number (2787900192).

Almost surely, 2^21666563467 is an apocalyptic number.

21666563467 is a deficient number, since it is larger than the sum of its proper divisors (636638069).

21666563467 is a wasteful number, since it uses less digits than its factorization.

21666563467 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3017417.

The product of its digits is 6531840, while the sum is 52.

The spelling of 21666563467 in words is "twenty-one billion, six hundred sixty-six million, five hundred sixty-three thousand, four hundred sixty-seven".