21676705 has 4 divisors (see below), whose sum is σ = 26012052. Its totient is φ = 17341360.

The previous prime is 21676703. The next prime is 21676747. The reversal of 21676705 is 50767612.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8946081 + 12730624 = 2991^2 + 3568^2 .

It is not a de Polignac number, because 21676705 - 2¹ = 21676703 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21676703) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2167666 + ... + 2167675.

It is an arithmetic number, because the mean of its divisors is an integer number (6503013).

Almost surely, 2^21676705 is an apocalyptic number.

It is an amenable number.

21676705 is a deficient number, since it is larger than the sum of its proper divisors (4335347).

21676705 is an equidigital number, since it uses as much as digits as its factorization.

21676705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4335346.

The product of its (nonzero) digits is 17640, while the sum is 34.

The square root of 21676705 is about 4655.8248463618. The cubic root of 21676705 is about 278.8246008110.

The spelling of 21676705 in words is "twenty-one million, six hundred seventy-six thousand, seven hundred five".