21544394 has 8 divisors (see below), whose sum is σ = 32926500. Its totient is φ = 10568896.

The previous prime is 21544373. The next prime is 21544403. The reversal of 21544394 is 49344512.

It can be written as a sum of positive squares in 2 ways, for example, as 20367169 + 1177225 = 4513^2 + 1085^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21544394.

It is an unprimeable number.

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, 101519 + ... + 101730.

Almost surely, 2^21544394 is an apocalyptic number.

21544394 is a deficient number, since it is larger than the sum of its proper divisors (11382106).

21544394 is a wasteful number, since it uses less digits than its factorization.

21544394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203304.

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

The square root of 21544394 is about 4641.5939072694. The cubic root of 21544394 is about 278.2561429925.

The spelling of 21544394 in words is "twenty-one million, five hundred forty-four thousand, three hundred ninety-four".