21535645 has 8 divisors (see below), whose sum is σ = 27203040. Its totient is φ = 16321680.

The previous prime is 21535643. The next prime is 21535663. The reversal of 21535645 is 54653512.

21535645 = 1463² + 1464² + ... + 1472².

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

It is not a de Polignac number, because 21535645 - 2¹ = 21535643 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21535643) by changing a digit.

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, 113251 + ... + 113440.

It is an arithmetic number, because the mean of its divisors is an integer number (3400380).

Almost surely, 2^21535645 is an apocalyptic number.

It is an amenable number.

21535645 is a deficient number, since it is larger than the sum of its proper divisors (5667395).

21535645 is a wasteful number, since it uses less digits than its factorization.

21535645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226715.

The product of its digits is 18000, while the sum is 31.

The square root of 21535645 is about 4640.6513551440. The cubic root of 21535645 is about 278.2184720542.

The spelling of 21535645 in words is "twenty-one million, five hundred thirty-five thousand, six hundred forty-five".