64920191 has 16 divisors (see below), whose sum is σ = 77760000. Its totient is φ = 52993248.

The previous prime is 64920187. The next prime is 64920209. The reversal of 64920191 is 19102946.

It is not a de Polignac number, because 64920191 - 2² = 64920187 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 (64920491) 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 15 ways as a sum of consecutive naturals, for example, 42560 + ... + 44058.

It is an arithmetic number, because the mean of its divisors is an integer number (4860000).

Almost surely, 2^64920191 is an apocalyptic number.

64920191 is a deficient number, since it is larger than the sum of its proper divisors (12839809).

64920191 is a wasteful number, since it uses less digits than its factorization.

64920191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1798.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 64920191 is about 8057.3066839981. The cubic root of 64920191 is about 401.9079494360.

The spelling of 64920191 in words is "sixty-four million, nine hundred twenty thousand, one hundred ninety-one".