63965821 has 4 divisors (see below), whose sum is σ = 63982044. Its totient is φ = 63949600.

The previous prime is 63965819. The next prime is 63965827. The reversal of 63965821 is 12856936.

63965821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 49632025 + 14333796 = 7045^2 + 3786^2 .

It is a cyclic number.

It is not a de Polignac number, because 63965821 - 2¹ = 63965819 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63965827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2031 + ... + 11491.

It is an arithmetic number, because the mean of its divisors is an integer number (15995511).

Almost surely, 2^63965821 is an apocalyptic number.

It is an amenable number.

63965821 is a deficient number, since it is larger than the sum of its proper divisors (16223).

63965821 is an equidigital number, since it uses as much as digits as its factorization.

63965821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16222.

The product of its digits is 77760, while the sum is 40.

The square root of 63965821 is about 7997.8635272178. The cubic root of 63965821 is about 399.9287810704.

The spelling of 63965821 in words is "sixty-three million, nine hundred sixty-five thousand, eight hundred twenty-one".