21667706 has 4 divisors (see below), whose sum is σ = 32501562. Its totient is φ = 10833852.

The previous prime is 21667703. The next prime is 21667739. The reversal of 21667706 is 60776612.

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

It can be written as a sum of positive squares in only one way, i.e., 20748025 + 919681 = 4555^2 + 959^2 .

It is not an unprimeable number, because it can be changed into a prime (21667703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5416925 + ... + 5416928.

Almost surely, 2^21667706 is an apocalyptic number.

21667706 is a deficient number, since it is larger than the sum of its proper divisors (10833856).

21667706 is a wasteful number, since it uses less digits than its factorization.

21667706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10833855.

The product of its (nonzero) digits is 21168, while the sum is 35.

The square root of 21667706 is about 4654.8583222264. The cubic root of 21667706 is about 278.7860111533.

The spelling of 21667706 in words is "twenty-one million, six hundred sixty-seven thousand, seven hundred six".