64988821 has 4 divisors (see below), whose sum is σ = 65500672. Its totient is φ = 64476972.

The previous prime is 64988801. The next prime is 64988843. The reversal of 64988821 is 12888946.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 64988821 - 2⁹ = 64988309 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 (64988801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 255735 + ... + 255988.

It is an arithmetic number, because the mean of its divisors is an integer number (16375168).

Almost surely, 2^64988821 is an apocalyptic number.

It is an amenable number.

64988821 is a deficient number, since it is larger than the sum of its proper divisors (511851).

64988821 is a wasteful number, since it uses less digits than its factorization.

64988821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 511850.

The product of its digits is 221184, while the sum is 46.

The square root of 64988821 is about 8061.5644263381. The cubic root of 64988821 is about 402.0495244383.

The spelling of 64988821 in words is "sixty-four million, nine hundred eighty-eight thousand, eight hundred twenty-one".