64185981 has 8 divisors (see below), whose sum is σ = 85681344. Its totient is φ = 42740640.

The previous prime is 64185959. The next prime is 64185991. The reversal of 64185981 is 18958146.

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

It is not a de Polignac number, because 64185981 - 2¹⁰ = 64184957 is a prime.

It is a super-2 number, since 2×64185981² = 8239680313864722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64185911) 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, 9400 + ... + 14721.

It is an arithmetic number, because the mean of its divisors is an integer number (10710168).

Almost surely, 2^64185981 is an apocalyptic number.

It is an amenable number.

64185981 is a deficient number, since it is larger than the sum of its proper divisors (21495363).

64185981 is a wasteful number, since it uses less digits than its factorization.

64185981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25011.

The product of its digits is 69120, while the sum is 42.

The square root of 64185981 is about 8011.6153801839. The cubic root of 64185981 is about 400.3870857075.

The spelling of 64185981 in words is "sixty-four million, one hundred eighty-five thousand, nine hundred eighty-one".