21064289 has 4 divisors (see below), whose sum is σ = 21073920. Its totient is φ = 21054660.

The previous prime is 21064273. The next prime is 21064291. The reversal of 21064289 is 98246012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21064289 - 2⁴ = 21064273 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21064249) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224 + ... + 6494.

It is an arithmetic number, because the mean of its divisors is an integer number (5268480).

Almost surely, 2^21064289 is an apocalyptic number.

It is an amenable number.

21064289 is a deficient number, since it is larger than the sum of its proper divisors (9631).

21064289 is an equidigital number, since it uses as much as digits as its factorization.

21064289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9630.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 21064289 is about 4589.5848396124. The cubic root of 21064289 is about 276.1736680922.

The spelling of 21064289 in words is "twenty-one million, sixty-four thousand, two hundred eighty-nine".