21495473 has 4 divisors (see below), whose sum is σ = 21510900. Its totient is φ = 21480048.

The previous prime is 21495469. The next prime is 21495499. The reversal of 21495473 is 37459412.

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 4048144 + 17447329 = 2012^2 + 4177^2 .

It is a cyclic number.

It is not a de Polignac number, because 21495473 - 2² = 21495469 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21495413) 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, 5390 + ... + 8487.

It is an arithmetic number, because the mean of its divisors is an integer number (5377725).

Almost surely, 2^21495473 is an apocalyptic number.

It is an amenable number.

21495473 is a deficient number, since it is larger than the sum of its proper divisors (15427).

21495473 is a wasteful number, since it uses less digits than its factorization.

21495473 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15426.

The product of its digits is 30240, while the sum is 35.

The square root of 21495473 is about 4636.3210630844. The cubic root of 21495473 is about 278.0453706809.

The spelling of 21495473 in words is "twenty-one million, four hundred ninety-five thousand, four hundred seventy-three".