21694963 has 4 divisors (see below), whose sum is σ = 21705408. Its totient is φ = 21684520.

The previous prime is 21694951. The next prime is 21694991. The reversal of 21694963 is 36949612.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21694963 - 2⁵ = 21694931 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 (21694663) 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 in 3 ways as a sum of consecutive naturals, for example, 931 + ... + 6652.

It is an arithmetic number, because the mean of its divisors is an integer number (5426352).

Almost surely, 2^21694963 is an apocalyptic number.

21694963 is a deficient number, since it is larger than the sum of its proper divisors (10445).

21694963 is an equidigital number, since it uses as much as digits as its factorization.

21694963 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10444.

The product of its digits is 69984, while the sum is 40.

The square root of 21694963 is about 4657.7852032914. The cubic root of 21694963 is about 278.9028622585.

The spelling of 21694963 in words is "twenty-one million, six hundred ninety-four thousand, nine hundred sixty-three".