64681787 has 4 divisors (see below), whose sum is σ = 68486616. Its totient is φ = 60876960.

The previous prime is 64681741. The next prime is 64681789. The reversal of 64681787 is 78718646.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64681787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64681789) 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, 1902389 + ... + 1902422.

It is an arithmetic number, because the mean of its divisors is an integer number (17121654).

Almost surely, 2^64681787 is an apocalyptic number.

64681787 is a deficient number, since it is larger than the sum of its proper divisors (3804829).

64681787 is a wasteful number, since it uses less digits than its factorization.

64681787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3804828.

The product of its digits is 451584, while the sum is 47.

The square root of 64681787 is about 8042.4988032327. The cubic root of 64681787 is about 401.4153754570.

The spelling of 64681787 in words is "sixty-four million, six hundred eighty-one thousand, seven hundred eighty-seven".