21166418 has 32 divisors (see below), whose sum is σ = 41139840. Its totient is φ = 7931520.

The previous prime is 21166381. The next prime is 21166441. The reversal of 21166418 is 81466112.

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, 398 + ... + 6518.

It is an arithmetic number, because the mean of its divisors is an integer number (1285620).

Almost surely, 2^21166418 is an apocalyptic number.

21166418 is a deficient number, since it is larger than the sum of its proper divisors (19973422).

21166418 is a wasteful number, since it uses less digits than its factorization.

21166418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6162.

The product of its digits is 2304, while the sum is 29.

The square root of 21166418 is about 4600.6975558061. The cubic root of 21166418 is about 276.6192860912.

The spelling of 21166418 in words is "twenty-one million, one hundred sixty-six thousand, four hundred eighteen".