64438813 has 2 divisors, whose sum is σ = 64438814. Its totient is φ = 64438812.

The previous prime is 64438807. The next prime is 64438837. The reversal of 64438813 is 31883446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64432729 + 6084 = 8027^2 + 78^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64438813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64438853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32219406 + 32219407.

It is an arithmetic number, because the mean of its divisors is an integer number (32219407).

Almost surely, 2^64438813 is an apocalyptic number.

It is an amenable number.

64438813 is a deficient number, since it is larger than the sum of its proper divisors (1).

64438813 is an equidigital number, since it uses as much as digits as its factorization.

64438813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55296, while the sum is 37.

The square root of 64438813 is about 8027.3789620274. The cubic root of 64438813 is about 400.9121122970.

The spelling of 64438813 in words is "sixty-four million, four hundred thirty-eight thousand, eight hundred thirteen".