64640243 has 2 divisors, whose sum is σ = 64640244. Its totient is φ = 64640242.

The previous prime is 64640227. The next prime is 64640263. The reversal of 64640243 is 34204646.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 64640243 - 2⁴ = 64640227 is a prime.

It is a super-2 number, since 2×64640243² = 8356722030198098, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (64640203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32320121 + 32320122.

It is an arithmetic number, because the mean of its divisors is an integer number (32320122).

Almost surely, 2^64640243 is an apocalyptic number.

64640243 is a deficient number, since it is larger than the sum of its proper divisors (1).

64640243 is an equidigital number, since it uses as much as digits as its factorization.

64640243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 29.

The square root of 64640243 is about 8039.9156090098. The cubic root of 64640243 is about 401.3294163191.

Adding to 64640243 its reverse (34204646), we get a palindrome (98844889).

The spelling of 64640243 in words is "sixty-four million, six hundred forty thousand, two hundred forty-three".