64308821 has 4 divisors (see below), whose sum is σ = 64945644. Its totient is φ = 63672000.

The previous prime is 64308809. The next prime is 64308833. The reversal of 64308821 is 12880346.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (64308809) and next prime (64308833).

It can be written as a sum of positive squares in 2 ways, for example, as 54316900 + 9991921 = 7370^2 + 3161^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64308821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64305821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 318260 + ... + 318461.

It is an arithmetic number, because the mean of its divisors is an integer number (16236411).

Almost surely, 2^64308821 is an apocalyptic number.

It is an amenable number.

64308821 is a deficient number, since it is larger than the sum of its proper divisors (636823).

64308821 is a wasteful number, since it uses less digits than its factorization.

64308821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 636822.

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 64308821 is about 8019.2780847156. The cubic root of 64308821 is about 400.6423450134.

It can be divided in two parts, 6430 and 8821, that added together give a palindrome (15251).

The spelling of 64308821 in words is "sixty-four million, three hundred eight thousand, eight hundred twenty-one".