64116581 has 4 divisors (see below), whose sum is σ = 64151052. Its totient is φ = 64082112.

The previous prime is 64116529. The next prime is 64116589. The reversal of 64116581 is 18561146.

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

It can be written as a sum of positive squares in 2 ways, for example, as 33535681 + 30580900 = 5791^2 + 5530^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64116581 is a prime.

It is a super-2 number, since 2×64116581² = 8221871918259122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64116589) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14276 + ... + 18221.

It is an arithmetic number, because the mean of its divisors is an integer number (16037763).

Almost surely, 2^64116581 is an apocalyptic number.

It is an amenable number.

64116581 is a deficient number, since it is larger than the sum of its proper divisors (34471).

64116581 is a wasteful number, since it uses less digits than its factorization.

64116581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34470.

The product of its digits is 5760, while the sum is 32.

The square root of 64116581 is about 8007.2829973718. The cubic root of 64116581 is about 400.2427297592.

It can be divided in two parts, 64116 and 581, that multiplied together give a triangular number (37251396 = T₈₆₃₁).

The spelling of 64116581 in words is "sixty-four million, one hundred sixteen thousand, five hundred eighty-one".