64715221 has 2 divisors, whose sum is σ = 64715222. Its totient is φ = 64715220.

The previous prime is 64715219. The next prime is 64715227. The reversal of 64715221 is 12251746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59074596 + 5640625 = 7686^2 + 2375^2 .

It is a cyclic number.

It is not a de Polignac number, because 64715221 - 2¹ = 64715219 is a prime.

Together with 64715219, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 64715221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64715227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32357610 + 32357611.

It is an arithmetic number, because the mean of its divisors is an integer number (32357611).

Almost surely, 2^64715221 is an apocalyptic number.

It is an amenable number.

64715221 is a deficient number, since it is larger than the sum of its proper divisors (1).

64715221 is an equidigital number, since it uses as much as digits as its factorization.

64715221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3360, while the sum is 28.

The square root of 64715221 is about 8044.5771175370. The cubic root of 64715221 is about 401.4845273802.

Adding to 64715221 its reverse (12251746), we get a palindrome (76966967).

The spelling of 64715221 in words is "sixty-four million, seven hundred fifteen thousand, two hundred twenty-one".