64691191 has 4 divisors (see below), whose sum is σ = 64723392. Its totient is φ = 64658992.

The previous prime is 64691189. The next prime is 64691201. The reversal of 64691191 is 19119646.

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

It is a cyclic number.

It is not a de Polignac number, because 64691191 - 2¹ = 64691189 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64691191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64691591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12871 + ... + 17176.

It is an arithmetic number, because the mean of its divisors is an integer number (16180848).

Almost surely, 2^64691191 is an apocalyptic number.

64691191 is a deficient number, since it is larger than the sum of its proper divisors (32201).

64691191 is a wasteful number, since it uses less digits than its factorization.

64691191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32200.

The product of its digits is 11664, while the sum is 37.

The square root of 64691191 is about 8043.0834261495. The cubic root of 64691191 is about 401.4348282656.

The spelling of 64691191 in words is "sixty-four million, six hundred ninety-one thousand, one hundred ninety-one".