64640919 has 24 divisors (see below), whose sum is σ = 104645248. Its totient is φ = 34761600.

The previous prime is 64640861. The next prime is 64640923. The reversal of 64640919 is 91904646.

It is not a de Polignac number, because 64640919 - 2¹³ = 64632727 is a prime.

It is a super-2 number, since 2×64640919² = 8356896818329122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64640119) 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 23 ways as a sum of consecutive naturals, for example, 744 + ... + 11394.

Almost surely, 2^64640919 is an apocalyptic number.

64640919 is a deficient number, since it is larger than the sum of its proper divisors (40004329).

64640919 is a wasteful number, since it uses less digits than its factorization.

64640919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10695 (or 10678 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 39.

The square root of 64640919 is about 8039.9576491422. The cubic root of 64640919 is about 401.3308153327.

The spelling of 64640919 in words is "sixty-four million, six hundred forty thousand, nine hundred nineteen".