21335645 has 8 divisors (see below), whose sum is σ = 25686456. Its totient is φ = 17012736.

The previous prime is 21335641. The next prime is 21335647. The reversal of 21335645 is 54653312.

It can be written as a sum of positive squares in 4 ways, for example, as 120409 + 21215236 = 347^2 + 4606^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21335645 - 2² = 21335641 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21335641) 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, 5252 + ... + 8381.

It is an arithmetic number, because the mean of its divisors is an integer number (3210807).

Almost surely, 2^21335645 is an apocalyptic number.

It is an amenable number.

21335645 is a deficient number, since it is larger than the sum of its proper divisors (4350811).

21335645 is a wasteful number, since it uses less digits than its factorization.

21335645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13951.

The product of its digits is 10800, while the sum is 29.

The square root of 21335645 is about 4619.0523919956. The cubic root of 21335645 is about 277.3545270044.

Adding to 21335645 its reverse (54653312), we get a palindrome (75988957).

The spelling of 21335645 in words is "twenty-one million, three hundred thirty-five thousand, six hundred forty-five".