21172650166 has 8 divisors (see below), whose sum is σ = 31760154720. Its totient is φ = 10585931928.

The previous prime is 21172650151. The next prime is 21172650179. The reversal of 21172650166 is 66105627112.

It is a happy number.

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

It is a super-2 number, since 2×21172650166² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 123886 + ... + 240193.

It is an arithmetic number, because the mean of its divisors is an integer number (3970019340).

Almost surely, 2^21172650166 is an apocalyptic number.

21172650166 is a deficient number, since it is larger than the sum of its proper divisors (10587504554).

21172650166 is a wasteful number, since it uses less digits than its factorization.

21172650166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 393158.

The product of its (nonzero) digits is 30240, while the sum is 37.

The spelling of 21172650166 in words is "twenty-one billion, one hundred seventy-two million, six hundred fifty thousand, one hundred sixty-six".