21017935666 has 16 divisors (see below), whose sum is σ = 38802343104. Its totient is φ = 8314787664.

The previous prime is 21017935651. The next prime is 21017935691. The reversal of 21017935666 is 66653971012.

It is a super-2 number, since 2×21017935666² (a number of 21 digits) contains 22 as substring.

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 7 ways as a sum of consecutive naturals, for example, 57741400 + ... + 57741763.

It is an arithmetic number, because the mean of its divisors is an integer number (2425146444).

Almost surely, 2^21017935666 is an apocalyptic number.

21017935666 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21017935666 is a deficient number, since it is larger than the sum of its proper divisors (17784407438).

21017935666 is a wasteful number, since it uses less digits than its factorization.

21017935666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115483185.

The product of its (nonzero) digits is 408240, while the sum is 46.

The spelling of 21017935666 in words is "twenty-one billion, seventeen million, nine hundred thirty-five thousand, six hundred sixty-six".