64904221 has 2 divisors, whose sum is σ = 64904222. Its totient is φ = 64904220.

The previous prime is 64904219. The next prime is 64904263. The reversal of 64904221 is 12240946.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57002500 + 7901721 = 7550^2 + 2811^2 .

It is a cyclic number.

It is not a de Polignac number, because 64904221 - 2¹ = 64904219 is a prime.

Together with 64904219, 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 64904221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64904821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32452110 + 32452111.

It is an arithmetic number, because the mean of its divisors is an integer number (32452111).

Almost surely, 2^64904221 is an apocalyptic number.

It is an amenable number.

64904221 is a deficient number, since it is larger than the sum of its proper divisors (1).

64904221 is an equidigital number, since it uses as much as digits as its factorization.

64904221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 64904221 is about 8056.3155970952. The cubic root of 64904221 is about 401.8749910388.

The spelling of 64904221 in words is "sixty-four million, nine hundred four thousand, two hundred twenty-one".