64640475 has 18 divisors (see below), whose sum is σ = 115778676. Its totient is φ = 34474800.

The previous prime is 64640473. The next prime is 64640497. The reversal of 64640475 is 57404646.

64640475 is a `hidden beast` number, since 6 + 4 + 640 + 4 + 7 + 5 = 666.

It is not a de Polignac number, because 64640475 - 2¹ = 64640473 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64640473) 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 17 ways as a sum of consecutive naturals, for example, 143421 + ... + 143870.

Almost surely, 2^64640475 is an apocalyptic number.

64640475 is a deficient number, since it is larger than the sum of its proper divisors (51138201).

64640475 is a wasteful number, since it uses less digits than its factorization.

64640475 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287307 (or 287299 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 36.

The square root of 64640475 is about 8039.9300370090. The cubic root of 64640475 is about 401.3298964550.

The spelling of 64640475 in words is "sixty-four million, six hundred forty thousand, four hundred seventy-five".