64721369 has 2 divisors, whose sum is σ = 64721370. Its totient is φ = 64721368.

The previous prime is 64721357. The next prime is 64721383. The reversal of 64721369 is 96312746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53465344 + 11256025 = 7312^2 + 3355^2 .

It is a cyclic number.

It is not a de Polignac number, because 64721369 - 2⁸ = 64721113 is a prime.

It is a super-2 number, since 2×64721369² = 8377711210468322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (64721309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32360684 + 32360685.

It is an arithmetic number, because the mean of its divisors is an integer number (32360685).

Almost surely, 2^64721369 is an apocalyptic number.

It is an amenable number.

64721369 is a deficient number, since it is larger than the sum of its proper divisors (1).

64721369 is an equidigital number, since it uses as much as digits as its factorization.

64721369 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 38.

The square root of 64721369 is about 8044.9592292317. The cubic root of 64721369 is about 401.4972407660.

The spelling of 64721369 in words is "sixty-four million, seven hundred twenty-one thousand, three hundred sixty-nine".