21668347 has 8 divisors (see below), whose sum is σ = 22346432. Its totient is φ = 20995200.

The previous prime is 21668327. The next prime is 21668389. The reversal of 21668347 is 74386612.

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

It is a cyclic number.

It is not a de Polignac number, because 21668347 - 2¹⁹ = 21144059 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21668327) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8947 + ... + 11107.

It is an arithmetic number, because the mean of its divisors is an integer number (2793304).

Almost surely, 2^21668347 is an apocalyptic number.

21668347 is a deficient number, since it is larger than the sum of its proper divisors (678085).

21668347 is a wasteful number, since it uses less digits than its factorization.

21668347 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2469.

The product of its digits is 48384, while the sum is 37.

The square root of 21668347 is about 4654.9271745109. The cubic root of 21668347 is about 278.7887602532.

The spelling of 21668347 in words is "twenty-one million, six hundred sixty-eight thousand, three hundred forty-seven".