64998339821 has 2 divisors, whose sum is σ = 64998339822. Its totient is φ = 64998339820.

The previous prime is 64998339793. The next prime is 64998339919. The reversal of 64998339821 is 12893389946.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 36973905796 + 28024434025 = 192286^2 + 167405^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64998339821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64998339221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32499169910 + 32499169911.

It is an arithmetic number, because the mean of its divisors is an integer number (32499169911).

Almost surely, 2^64998339821 is an apocalyptic number.

It is an amenable number.

64998339821 is a deficient number, since it is larger than the sum of its proper divisors (1).

64998339821 is an equidigital number, since it uses as much as digits as its factorization.

64998339821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20155392, while the sum is 62.

The spelling of 64998339821 in words is "sixty-four billion, nine hundred ninety-eight million, three hundred thirty-nine thousand, eight hundred twenty-one".