21908794 has 4 divisors (see below), whose sum is σ = 32863194. Its totient is φ = 10954396.

The previous prime is 21908791. The next prime is 21908797. The reversal of 21908794 is 49780912.

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

It is an interprime number because it is at equal distance from previous prime (21908791) and next prime (21908797).

It can be written as a sum of positive squares in only one way, i.e., 19035769 + 2873025 = 4363^2 + 1695^2 .

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 not an unprimeable number, because it can be changed into a prime (21908791) 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, 5477197 + ... + 5477200.

Almost surely, 2^21908794 is an apocalyptic number.

21908794 is a deficient number, since it is larger than the sum of its proper divisors (10954400).

21908794 is a wasteful number, since it uses less digits than its factorization.

21908794 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10954399.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 21908794 is about 4680.6830698094. The cubic root of 21908794 is about 279.8161803695.

The spelling of 21908794 in words is "twenty-one million, nine hundred eight thousand, seven hundred ninety-four".