64222721 has 2 divisors, whose sum is σ = 64222722. Its totient is φ = 64222720.

The previous prime is 64222709. The next prime is 64222729. The reversal of 64222721 is 12722246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41422096 + 22800625 = 6436^2 + 4775^2 .

It is a cyclic number.

It is not a de Polignac number, because 64222721 - 2¹⁸ = 63960577 is a prime.

It is not a weakly prime, because it can be changed into another prime (64222729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32111360 + 32111361.

It is an arithmetic number, because the mean of its divisors is an integer number (32111361).

Almost surely, 2^64222721 is an apocalyptic number.

It is an amenable number.

64222721 is a deficient number, since it is larger than the sum of its proper divisors (1).

64222721 is an equidigital number, since it uses as much as digits as its factorization.

64222721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 26.

The square root of 64222721 is about 8013.9079730179. The cubic root of 64222721 is about 400.4634648767.

Adding to 64222721 its reverse (12722246), we get a palindrome (76944967).

The spelling of 64222721 in words is "sixty-four million, two hundred twenty-two thousand, seven hundred twenty-one".