64043821 has 2 divisors, whose sum is σ = 64043822. Its totient is φ = 64043820.

The previous prime is 64043779. The next prime is 64043831. The reversal of 64043821 is 12834046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 45077796 + 18966025 = 6714^2 + 4355^2 .

It is a cyclic number.

It is not a de Polignac number, because 64043821 - 2¹⁵ = 64011053 is a prime.

It is a super-2 number, since 2×64043821² = 8203222016560082, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 64043821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64043831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32021910 + 32021911.

It is an arithmetic number, because the mean of its divisors is an integer number (32021911).

Almost surely, 2^64043821 is an apocalyptic number.

It is an amenable number.

64043821 is a deficient number, since it is larger than the sum of its proper divisors (1).

64043821 is an equidigital number, since it uses as much as digits as its factorization.

64043821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 64043821 is about 8002.7383438421. The cubic root of 64043821 is about 400.0912729216.

Adding to 64043821 its reverse (12834046), we get a palindrome (76877867).

The spelling of 64043821 in words is "sixty-four million, forty-three thousand, eight hundred twenty-one".