64986581 has 4 divisors (see below), whose sum is σ = 70894464. Its totient is φ = 59078700.

The previous prime is 64986491. The next prime is 64986587. The reversal of 64986581 is 18568946.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 64986581 - 2¹⁴ = 64970197 is a prime.

It is a super-2 number, since 2×64986581² = 8446511420139122, 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 (64986587) 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, 2953925 + ... + 2953946.

It is an arithmetic number, because the mean of its divisors is an integer number (17723616).

Almost surely, 2^64986581 is an apocalyptic number.

It is an amenable number.

64986581 is a deficient number, since it is larger than the sum of its proper divisors (5907883).

64986581 is a wasteful number, since it uses less digits than its factorization.

64986581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5907882.

The product of its digits is 414720, while the sum is 47.

The square root of 64986581 is about 8061.4254942907. The cubic root of 64986581 is about 402.0449051757.

It can be divided in two parts, 649865 and 81, that added together give a palindrome (649946).

The spelling of 64986581 in words is "sixty-four million, nine hundred eighty-six thousand, five hundred eighty-one".