21967805 has 8 divisors (see below), whose sum is σ = 26439000. Its totient is φ = 17522496.

The previous prime is 21967801. The next prime is 21967807. The reversal of 21967805 is 50876912.

It can be written as a sum of positive squares in 4 ways, for example, as 835396 + 21132409 = 914^2 + 4597^2 .

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 21967805 - 2² = 21967801 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21967801) 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, 4550 + ... + 8039.

It is an arithmetic number, because the mean of its divisors is an integer number (3304875).

Almost surely, 2^21967805 is an apocalyptic number.

It is an amenable number.

21967805 is a deficient number, since it is larger than the sum of its proper divisors (4471195).

21967805 is a wasteful number, since it uses less digits than its factorization.

21967805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12943.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 21967805 is about 4686.9825047679. The cubic root of 21967805 is about 280.0671820086.

It can be divided in two parts, 2196 and 7805, that added together give a palindrome (10001).

The spelling of 21967805 in words is "twenty-one million, nine hundred sixty-seven thousand, eight hundred five".