64634821 has 4 divisors (see below), whose sum is σ = 64672972. Its totient is φ = 64596672.

The previous prime is 64634809. The next prime is 64634831. The reversal of 64634821 is 12843646.

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

It can be written as a sum of positive squares in 2 ways, for example, as 38266596 + 26368225 = 6186^2 + 5135^2 .

It is a cyclic number.

It is not a de Polignac number, because 64634821 - 2²⁵ = 31080389 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 (64634831) 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, 16410 + ... + 19963.

It is an arithmetic number, because the mean of its divisors is an integer number (16168243).

Almost surely, 2^64634821 is an apocalyptic number.

It is an amenable number.

64634821 is a deficient number, since it is larger than the sum of its proper divisors (38151).

64634821 is a wasteful number, since it uses less digits than its factorization.

64634821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38150.

The product of its digits is 27648, while the sum is 34.

The square root of 64634821 is about 8039.5784093446. The cubic root of 64634821 is about 401.3181948837.

The spelling of 64634821 in words is "sixty-four million, six hundred thirty-four thousand, eight hundred twenty-one".