64891866 has 64 divisors (see below), whose sum is σ = 147603456. Its totient is φ = 18878400.

The previous prime is 64891847. The next prime is 64891891. The reversal of 64891866 is 66819846.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 113361 + ... + 113931.

It is an arithmetic number, because the mean of its divisors is an integer number (2306304).

Almost surely, 2^64891866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64891866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73801728).

64891866 is an abundant number, since it is smaller than the sum of its proper divisors (82711590).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

64891866 is a wasteful number, since it uses less digits than its factorization.

64891866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 667.

The product of its digits is 497664, while the sum is 48.

The square root of 64891866 is about 8055.5487708784. The cubic root of 64891866 is about 401.8494894586.

The spelling of 64891866 in words is "sixty-four million, eight hundred ninety-one thousand, eight hundred sixty-six".