21064287 has 8 divisors (see below), whose sum is σ = 28144000. Its totient is φ = 14013720.

The previous prime is 21064273. The next prime is 21064291. The reversal of 21064287 is 78246012.

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

It is not a de Polignac number, because 21064287 - 2⁴ = 21064271 is a prime.

It is a Duffinian number.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21064247) 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, 5539 + ... + 8532.

It is an arithmetic number, because the mean of its divisors is an integer number (3518000).

Almost surely, 2^21064287 is an apocalyptic number.

21064287 is a deficient number, since it is larger than the sum of its proper divisors (7079713).

21064287 is a wasteful number, since it uses less digits than its factorization.

21064287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14573.

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 21064287 is about 4589.5846217278. The cubic root of 21064287 is about 276.1736593516.

The spelling of 21064287 in words is "twenty-one million, sixty-four thousand, two hundred eighty-seven".