21723622666 has 8 divisors (see below), whose sum is σ = 32587238340. Its totient is φ = 10861209888.

The previous prime is 21723622637. The next prime is 21723622699. The reversal of 21723622666 is 66622632712.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17682350625 + 4041272041 = 132975^2 + 63571^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 254131 + ... + 328678.

Almost surely, 2^21723622666 is an apocalyptic number.

21723622666 is a deficient number, since it is larger than the sum of its proper divisors (10863615674).

21723622666 is a wasteful number, since it uses less digits than its factorization.

21723622666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 601448.

The product of its digits is 435456, while the sum is 43.

The spelling of 21723622666 in words is "twenty-one billion, seven hundred twenty-three million, six hundred twenty-two thousand, six hundred sixty-six".