21716473 has 4 divisors (see below), whose sum is σ = 21726208. Its totient is φ = 21706740.

The previous prime is 21716441. The next prime is 21716477. The reversal of 21716473 is 37461712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, 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 21716473 - 2⁵ = 21716441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21716477) 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, 328 + ... + 6598.

It is an arithmetic number, because the mean of its divisors is an integer number (5431552).

Almost surely, 2^21716473 is an apocalyptic number.

It is an amenable number.

21716473 is a deficient number, since it is larger than the sum of its proper divisors (9735).

21716473 is an equidigital number, since it uses as much as digits as its factorization.

21716473 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9734.

The product of its digits is 7056, while the sum is 31.

The square root of 21716473 is about 4660.0936685865. The cubic root of 21716473 is about 278.9950068264.

The spelling of 21716473 in words is "twenty-one million, seven hundred sixteen thousand, four hundred seventy-three".