21394445 has 8 divisors (see below), whose sum is σ = 25751544. Its totient is φ = 17063424.

The previous prime is 21394427. The next prime is 21394453. The reversal of 21394445 is 54449312.

It can be written as a sum of positive squares in 4 ways, for example, as 40804 + 21353641 = 202^2 + 4621^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21394445 - 2⁸ = 21394189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4664 + ... + 8033.

It is an arithmetic number, because the mean of its divisors is an integer number (3218943).

Almost surely, 2^21394445 is an apocalyptic number.

It is an amenable number.

21394445 is a deficient number, since it is larger than the sum of its proper divisors (4357099).

21394445 is a wasteful number, since it uses less digits than its factorization.

21394445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13039.

The product of its digits is 17280, while the sum is 32.

The square root of 21394445 is about 4625.4129545371. The cubic root of 21394445 is about 277.6090851600.

The spelling of 21394445 in words is "twenty-one million, three hundred ninety-four thousand, four hundred forty-five".