21435545 has 16 divisors (see below), whose sum is σ = 26236560. Its totient is φ = 16809984.

The previous prime is 21435529. The next prime is 21435551. The reversal of 21435545 is 54553412.

It can be written as a sum of positive squares in 8 ways, for example, as 17161 + 21418384 = 131^2 + 4628^2 .

It is a cyclic number.

It is not a de Polignac number, because 21435545 - 2⁴ = 21435529 is a prime.

It is a Curzon 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 15 ways as a sum of consecutive naturals, for example, 93491 + ... + 93719.

It is an arithmetic number, because the mean of its divisors is an integer number (1639785).

Almost surely, 2^21435545 is an apocalyptic number.

It is an amenable number.

21435545 is a deficient number, since it is larger than the sum of its proper divisors (4801015).

21435545 is a wasteful number, since it uses less digits than its factorization.

21435545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 524.

The product of its digits is 12000, while the sum is 29.

The square root of 21435545 is about 4629.8536693939. The cubic root of 21435545 is about 277.7867392961.

Adding to 21435545 its reverse (54553412), we get a palindrome (75988957).

The spelling of 21435545 in words is "twenty-one million, four hundred thirty-five thousand, five hundred forty-five".