21064523 has 2 divisors, whose sum is σ = 21064524. Its totient is φ = 21064522.

The previous prime is 21064499. The next prime is 21064553. The reversal of 21064523 is 32546012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21064523 - 2²² = 16870219 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21064553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10532261 + 10532262.

It is an arithmetic number, because the mean of its divisors is an integer number (10532262).

Almost surely, 2^21064523 is an apocalyptic number.

21064523 is a deficient number, since it is larger than the sum of its proper divisors (1).

21064523 is an equidigital number, since it uses as much as digits as its factorization.

21064523 is an evil number, because the sum of its binary digits is even.

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

The square root of 21064523 is about 4589.6103320435. The cubic root of 21064523 is about 276.1746907456.

The spelling of 21064523 in words is "twenty-one million, sixty-four thousand, five hundred twenty-three".