21668085 has 12 divisors (see below), whose sum is σ = 37558092. Its totient is φ = 11556288.

The previous prime is 21668033. The next prime is 21668099. The reversal of 21668085 is 58086612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 12341169 + 9326916 = 3513^2 + 3054^2 .

It is not a de Polignac number, because 21668085 - 2¹¹ = 21666037 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 240712 + ... + 240801.

It is an arithmetic number, because the mean of its divisors is an integer number (3129841).

Almost surely, 2^21668085 is an apocalyptic number.

It is an amenable number.

21668085 is a deficient number, since it is larger than the sum of its proper divisors (15890007).

21668085 is a wasteful number, since it uses less digits than its factorization.

21668085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481524 (or 481521 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 21668085 is about 4654.8990322025. The cubic root of 21668085 is about 278.7876366027.

The spelling of 21668085 in words is "twenty-one million, six hundred sixty-eight thousand, eighty-five".