21416545 has 8 divisors (see below), whose sum is σ = 25954920. Its totient is φ = 16963200.

The previous prime is 21416543. The next prime is 21416561. The reversal of 21416545 is 54561412.

It can be written as a sum of positive squares in 4 ways, for example, as 9138529 + 12278016 = 3023^2 + 3504^2 .

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

It is not a de Polignac number, because 21416545 - 2¹ = 21416543 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (21416543) by changing a digit.

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, 20700 + ... + 21709.

It is an arithmetic number, because the mean of its divisors is an integer number (3244365).

Almost surely, 2^21416545 is an apocalyptic number.

It is an amenable number.

21416545 is a deficient number, since it is larger than the sum of its proper divisors (4538375).

21416545 is a wasteful number, since it uses less digits than its factorization.

21416545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42515.

The product of its digits is 4800, while the sum is 28.

The square root of 21416545 is about 4627.8013137990. The cubic root of 21416545 is about 277.7046403302.

Adding to 21416545 its reverse (54561412), we get a palindrome (75977957).

The spelling of 21416545 in words is "twenty-one million, four hundred sixteen thousand, five hundred forty-five".