64639191 has 16 divisors (see below), whose sum is σ = 88563200. Its totient is φ = 41935320.

The previous prime is 64639189. The next prime is 64639207. The reversal of 64639191 is 19193646.

It is not a de Polignac number, because 64639191 - 2¹ = 64639189 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 (64635191) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 238386 + ... + 238656.

It is an arithmetic number, because the mean of its divisors is an integer number (5535200).

Almost surely, 2^64639191 is an apocalyptic number.

64639191 is a deficient number, since it is larger than the sum of its proper divisors (23924009).

64639191 is an frugal number, since it uses more digits than its factorization.

64639191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403 (or 317 counting only the distinct ones).

The product of its digits is 34992, while the sum is 39.

The square root of 64639191 is about 8039.8501851714. The cubic root of 64639191 is about 401.3272391365.

The spelling of 64639191 in words is "sixty-four million, six hundred thirty-nine thousand, one hundred ninety-one".