21706166684 has 12 divisors (see below), whose sum is σ = 37987707408. Its totient is φ = 10852536000.

The previous prime is 21706166653. The next prime is 21706166687. The reversal of 21706166684 is 48666160712.

It is a super-2 number, since 2×21706166684² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21706166687) 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 3 ways as a sum of consecutive naturals, for example, 39992 + ... + 212159.

It is an arithmetic number, because the mean of its divisors is an integer number (3165642284).

Almost surely, 2^21706166684 is an apocalyptic number.

It is an amenable number.

21706166684 is a deficient number, since it is larger than the sum of its proper divisors (16281540724).

21706166684 is a wasteful number, since it uses less digits than its factorization.

21706166684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273676 (or 273674 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 47.

The spelling of 21706166684 in words is "twenty-one billion, seven hundred six million, one hundred sixty-six thousand, six hundred eighty-four".