21916273 has 4 divisors (see below), whose sum is σ = 21943540. Its totient is φ = 21889008.

The previous prime is 21916267. The next prime is 21916313. The reversal of 21916273 is 37261912.

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 15626209 + 6290064 = 3953^2 + 2508^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21916273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21916243) 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, 12390 + ... + 14047.

It is an arithmetic number, because the mean of its divisors is an integer number (5485885).

Almost surely, 2^21916273 is an apocalyptic number.

It is an amenable number.

21916273 is a deficient number, since it is larger than the sum of its proper divisors (27267).

21916273 is an equidigital number, since it uses as much as digits as its factorization.

21916273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27266.

The product of its digits is 4536, while the sum is 31.

The square root of 21916273 is about 4681.4819234939. The cubic root of 21916273 is about 279.8480170089.

It can be divided in two parts, 2191 and 6273, that added together give a square (8464 = 92²).

The spelling of 21916273 in words is "twenty-one million, nine hundred sixteen thousand, two hundred seventy-three".