64436581 has 8 divisors (see below), whose sum is σ = 73994400. Its totient is φ = 55495440.

The previous prime is 64436539. The next prime is 64436609. The reversal of 64436581 is 18563446.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 64436581 - 2⁷ = 64436453 is a prime.

It is a super-2 number, since 2×64436581² = 8304145941939122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64436581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64416581) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 153946 + ... + 154363.

It is an arithmetic number, because the mean of its divisors is an integer number (9249300).

Almost surely, 2^64436581 is an apocalyptic number.

It is an amenable number.

64436581 is a deficient number, since it is larger than the sum of its proper divisors (9557819).

64436581 is a wasteful number, since it uses less digits than its factorization.

64436581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308339.

The product of its digits is 69120, while the sum is 37.

The square root of 64436581 is about 8027.2399366158. The cubic root of 64436581 is about 400.9074833778.

It can be divided in two parts, 644365 and 81, that added together give a palindrome (644446).

The spelling of 64436581 in words is "sixty-four million, four hundred thirty-six thousand, five hundred eighty-one".