64218681 has 12 divisors (see below), whose sum is σ = 93317952. Its totient is φ = 42555096.

The previous prime is 64218667. The next prime is 64218697. The reversal of 64218681 is 18681246.

64218681 is a `hidden beast` number, since 642 + 1 + 8 + 6 + 8 + 1 = 666.

It is not a de Polignac number, because 64218681 - 2⁶ = 64218617 is a prime.

It is a super-2 number, since 2×64218681² = 8248077978759522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (64218481) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19861 + ... + 22866.

It is an arithmetic number, because the mean of its divisors is an integer number (7776496).

Almost surely, 2^64218681 is an apocalyptic number.

It is an amenable number.

64218681 is a deficient number, since it is larger than the sum of its proper divisors (29099271).

64218681 is a wasteful number, since it uses less digits than its factorization.

64218681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42900 (or 42897 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 64218681 is about 8013.6559072623. The cubic root of 64218681 is about 400.4550675043.

The spelling of 64218681 in words is "sixty-four million, two hundred eighteen thousand, six hundred eighty-one".