21606693 has 8 divisors (see below), whose sum is σ = 28939008. Its totient is φ = 14339424.

The previous prime is 21606691. The next prime is 21606701. The reversal of 21606693 is 39660612.

It is a happy number.

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

It is not a de Polignac number, because 21606693 - 2¹ = 21606691 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21606691) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 15480 + ... + 16817.

It is an arithmetic number, because the mean of its divisors is an integer number (3617376).

Almost surely, 2^21606693 is an apocalyptic number.

It is an amenable number.

21606693 is a deficient number, since it is larger than the sum of its proper divisors (7332315).

21606693 is a wasteful number, since it uses less digits than its factorization.

21606693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32523.

The product of its (nonzero) digits is 11664, while the sum is 33.

The square root of 21606693 is about 4648.3000118323. The cubic root of 21606693 is about 278.5240920037.

The spelling of 21606693 in words is "twenty-one million, six hundred six thousand, six hundred ninety-three".