21166408 has 16 divisors (see below), whose sum is σ = 39744000. Its totient is φ = 10568016.

The previous prime is 21166381. The next prime is 21166441. The reversal of 21166408 is 80466112.

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 3 ways as a sum of consecutive naturals, for example, 5913 + ... + 8791.

It is an arithmetic number, because the mean of its divisors is an integer number (2484000).

Almost surely, 2^21166408 is an apocalyptic number.

It is an amenable number.

21166408 is a deficient number, since it is larger than the sum of its proper divisors (18577592).

21166408 is a wasteful number, since it uses less digits than its factorization.

21166408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3804 (or 3800 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 21166408 is about 4600.6964690142. The cubic root of 21166408 is about 276.6192425286.

The spelling of 21166408 in words is "twenty-one million, one hundred sixty-six thousand, four hundred eight".