21661659267 has 8 divisors (see below), whose sum is σ = 30581166096. Its totient is φ = 13591629312.

The previous prime is 21661659223. The next prime is 21661659277. The reversal of 21661659267 is 76295616612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21661659267 - 2¹⁵ = 21661626499 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (51), and also a Moran number because the ratio is a prime number: 424738417 = 21661659267 / (2 + 1 + 6 + 6 + 1 + 6 + 5 + 9 + 2 + 6 + 7).

It is not an unprimeable number, because it can be changed into a prime (21661659277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 212369158 + ... + 212369259.

It is an arithmetic number, because the mean of its divisors is an integer number (3822645762).

Almost surely, 2^21661659267 is an apocalyptic number.

21661659267 is a deficient number, since it is larger than the sum of its proper divisors (8919506829).

21661659267 is a wasteful number, since it uses less digits than its factorization.

21661659267 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424738437.

The product of its digits is 1632960, while the sum is 51.

The spelling of 21661659267 in words is "twenty-one billion, six hundred sixty-one million, six hundred fifty-nine thousand, two hundred sixty-seven".