64947521 has 2 divisors, whose sum is σ = 64947522. Its totient is φ = 64947520.

The previous prime is 64947517. The next prime is 64947523. The reversal of 64947521 is 12574946.

64947521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50922496 + 14025025 = 7136^2 + 3745^2 .

It is a cyclic number.

It is not a de Polignac number, because 64947521 - 2² = 64947517 is a prime.

Together with 64947523, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (64947523) 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 as a sum of consecutive naturals, namely, 32473760 + 32473761.

It is an arithmetic number, because the mean of its divisors is an integer number (32473761).

Almost surely, 2^64947521 is an apocalyptic number.

It is an amenable number.

64947521 is a deficient number, since it is larger than the sum of its proper divisors (1).

64947521 is an equidigital number, since it uses as much as digits as its factorization.

64947521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480, while the sum is 38.

The square root of 64947521 is about 8059.0024816971. The cubic root of 64947521 is about 401.9643397161.

The spelling of 64947521 in words is "sixty-four million, nine hundred forty-seven thousand, five hundred twenty-one".