21667606 has 4 divisors (see below), whose sum is σ = 32501412. Its totient is φ = 10833802.

The previous prime is 21667603. The next prime is 21667649. The reversal of 21667606 is 60676612.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21667603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5416900 + ... + 5416903.

It is an arithmetic number, because the mean of its divisors is an integer number (8125353).

Almost surely, 2^21667606 is an apocalyptic number.

21667606 is a deficient number, since it is larger than the sum of its proper divisors (10833806).

21667606 is a wasteful number, since it uses less digits than its factorization.

21667606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10833805.

The product of its (nonzero) digits is 18144, while the sum is 34.

The square root of 21667606 is about 4654.8475807485. The cubic root of 21667606 is about 278.7855822716.

The spelling of 21667606 in words is "twenty-one million, six hundred sixty-seven thousand, six hundred six".