21305264 has 10 divisors (see below), whose sum is σ = 41278980. Its totient is φ = 10652624.

The previous prime is 21305261. The next prime is 21305279. The reversal of 21305264 is 46250312.

It is not an unprimeable number, because it can be changed into a prime (21305261) 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 as a sum of consecutive naturals, namely, 665774 + ... + 665805.

It is an arithmetic number, because the mean of its divisors is an integer number (4127898).

Almost surely, 2^21305264 is an apocalyptic number.

It is an amenable number.

21305264 is a deficient number, since it is larger than the sum of its proper divisors (19973716).

21305264 is a wasteful number, since it uses less digits than its factorization.

21305264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1331587 (or 1331581 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21305264 is about 4615.7625588845. The cubic root of 21305264 is about 277.2228176730. Note that the first 3 decimals are identical.

Adding to 21305264 its reverse (46250312), we get a palindrome (67555576).

The spelling of 21305264 in words is "twenty-one million, three hundred five thousand, two hundred sixty-four".