21154166 has 32 divisors (see below), whose sum is σ = 36391680. Its totient is φ = 9133600.

The previous prime is 21154157. The next prime is 21154187. The reversal of 21154166 is 66145112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45065 + ... + 45531.

It is an arithmetic number, because the mean of its divisors is an integer number (1137240).

Almost surely, 2^21154166 is an apocalyptic number.

21154166 is a deficient number, since it is larger than the sum of its proper divisors (15237514).

21154166 is a wasteful number, since it uses less digits than its factorization.

21154166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 580.

The product of its digits is 1440, while the sum is 26.

The square root of 21154166 is about 4599.3658258503. The cubic root of 21154166 is about 276.5659028873.

Adding to 21154166 its reverse (66145112), we get a palindrome (87299278).

The spelling of 21154166 in words is "twenty-one million, one hundred fifty-four thousand, one hundred sixty-six".