21544045 has 8 divisors (see below), whose sum is σ = 25877880. Its totient is φ = 17218560.

The previous prime is 21544037. The next prime is 21544057. The reversal of 21544045 is 54044512.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2725801 + 18818244 = 1651^2 + 4338^2 .

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

It is not a de Polignac number, because 21544045 - 2³ = 21544037 is a prime.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 8305 + ... + 10585.

It is an arithmetic number, because the mean of its divisors is an integer number (3234735).

Almost surely, 2^21544045 is an apocalyptic number.

It is an amenable number.

21544045 is a deficient number, since it is larger than the sum of its proper divisors (4333835).

21544045 is a wasteful number, since it uses less digits than its factorization.

21544045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4175.

The product of its (nonzero) digits is 3200, while the sum is 25.

The square root of 21544045 is about 4641.5563122729. The cubic root of 21544045 is about 278.2546404838.

Adding to 21544045 its reverse (54044512), we get a palindrome (75588557).

The spelling of 21544045 in words is "twenty-one million, five hundred forty-four thousand, forty-five".