64944981 has 24 divisors (see below), whose sum is σ = 101214360. Its totient is φ = 39975936.

The previous prime is 64944977. The next prime is 64945003. The reversal of 64944981 is 18944946.

It can be written as a sum of positive squares in 4 ways, for example, as 28836900 + 36108081 = 5370^2 + 6009^2 .

It is not a de Polignac number, because 64944981 - 2² = 64944977 is a prime.

It is a super-2 number, since 2×64944981² = 8435701114180722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64944181) 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 23 ways as a sum of consecutive naturals, for example, 4105 + ... + 12113.

It is an arithmetic number, because the mean of its divisors is an integer number (4217265).

Almost surely, 2^64944981 is an apocalyptic number.

It is an amenable number.

64944981 is a deficient number, since it is larger than the sum of its proper divisors (36269379).

64944981 is a wasteful number, since it uses less digits than its factorization.

64944981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8085 (or 8082 counting only the distinct ones).

The product of its digits is 248832, while the sum is 45.

The square root of 64944981 is about 8058.8448924148. The cubic root of 64944981 is about 401.9590995739.

The spelling of 64944981 in words is "sixty-four million, nine hundred forty-four thousand, nine hundred eighty-one".