64861581 has 8 divisors (see below), whose sum is σ = 87290784. Its totient is φ = 42836720.

The previous prime is 64861543. The next prime is 64861583. The reversal of 64861581 is 18516846.

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

It is a cyclic number.

It is not a de Polignac number, because 64861581 - 2¹⁰ = 64860557 is a prime.

It is a super-2 number, since 2×64861581² = 8414049379639122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64861583) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 100710 + ... + 101351.

It is an arithmetic number, because the mean of its divisors is an integer number (10911348).

Almost surely, 2^64861581 is an apocalyptic number.

It is an amenable number.

64861581 is a deficient number, since it is larger than the sum of its proper divisors (22429203).

64861581 is a wasteful number, since it uses less digits than its factorization.

64861581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202171.

The product of its digits is 46080, while the sum is 39.

The square root of 64861581 is about 8053.6687913025. The cubic root of 64861581 is about 401.7869654152.

The spelling of 64861581 in words is "sixty-four million, eight hundred sixty-one thousand, five hundred eighty-one".