21117966 has 8 divisors (see below), whose sum is σ = 42235944. Its totient is φ = 7039320.

The previous prime is 21117959. The next prime is 21117983. The reversal of 21117966 is 66971112.

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

21117966 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1759825 + ... + 1759836.

It is an arithmetic number, because the mean of its divisors is an integer number (5279493).

Almost surely, 2^21117966 is an apocalyptic number.

21117966 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21117966 is a wasteful number, since it uses less digits than its factorization.

21117966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3519666.

The product of its digits is 4536, while the sum is 33.

The square root of 21117966 is about 4595.4288156819. The cubic root of 21117966 is about 276.4080553039.

The spelling of 21117966 in words is "twenty-one million, one hundred seventeen thousand, nine hundred sixty-six".