64919191 has 4 divisors (see below), whose sum is σ = 64965384. Its totient is φ = 64873000.

The previous prime is 64919167. The next prime is 64919213. The reversal of 64919191 is 19191946.

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 64919191 - 2¹³ = 64910999 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 (64919161) 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, 20920 + ... + 23821.

It is an arithmetic number, because the mean of its divisors is an integer number (16241346).

Almost surely, 2^64919191 is an apocalyptic number.

64919191 is a deficient number, since it is larger than the sum of its proper divisors (46193).

64919191 is a wasteful number, since it uses less digits than its factorization.

64919191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46192.

The product of its digits is 17496, while the sum is 40.

The square root of 64919191 is about 8057.2446282833. The cubic root of 64919191 is about 401.9058858253.

The spelling of 64919191 in words is "sixty-four million, nine hundred nineteen thousand, one hundred ninety-one".