21226600665 has 32 divisors (see below), whose sum is σ = 37925856000. Its totient is φ = 11263950720.

The previous prime is 21226600657. The next prime is 21226600699. The reversal of 21226600665 is 56600662212.

21226600665 is a `hidden beast` number, since 21 + 2 + 26 + 600 + 6 + 6 + 5 = 666.

It is not a de Polignac number, because 21226600665 - 2³ = 21226600657 is a prime.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 368196 + ... + 421925.

It is an arithmetic number, because the mean of its divisors is an integer number (1185183000).

Almost surely, 2^21226600665 is an apocalyptic number.

It is an amenable number.

21226600665 is a deficient number, since it is larger than the sum of its proper divisors (16699255335).

21226600665 is a wasteful number, since it uses less digits than its factorization.

21226600665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 790334 (or 790328 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 21226600665 in words is "twenty-one billion, two hundred twenty-six million, six hundred thousand, six hundred sixty-five".