21371166 has 12 divisors (see below), whose sum is σ = 46304232. Its totient is φ = 7123716.

The previous prime is 21371153. The next prime is 21371171. The reversal of 21371166 is 66117312.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 593626 + ... + 593661.

It is an arithmetic number, because the mean of its divisors is an integer number (3858686).

Almost surely, 2^21371166 is an apocalyptic number.

21371166 is an abundant number, since it is smaller than the sum of its proper divisors (24933066).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21371166 is a wasteful number, since it uses less digits than its factorization.

21371166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1187295 (or 1187292 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 21371166 is about 4622.8958456794. The cubic root of 21371166 is about 277.5083610824.

Adding to 21371166 its reverse (66117312), we get a palindrome (87488478).

The spelling of 21371166 in words is "twenty-one million, three hundred seventy-one thousand, one hundred sixty-six".