64540081 has 2 divisors, whose sum is σ = 64540082. Its totient is φ = 64540080.

The previous prime is 64540079. The next prime is 64540087. The reversal of 64540081 is 18004546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50410000 + 14130081 = 7100^2 + 3759^2 .

It is a cyclic number.

It is not a de Polignac number, because 64540081 - 2¹ = 64540079 is a prime.

It is a super-2 number, since 2×64540081² = 8330844110973122, which contains 22 as substring.

Together with 64540079, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (64540087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32270040 + 32270041.

It is an arithmetic number, because the mean of its divisors is an integer number (32270041).

Almost surely, 2^64540081 is an apocalyptic number.

It is an amenable number.

64540081 is a deficient number, since it is larger than the sum of its proper divisors (1).

64540081 is an equidigital number, since it uses as much as digits as its factorization.

64540081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 64540081 is about 8033.6841486332. The cubic root of 64540081 is about 401.1220184935.

The spelling of 64540081 in words is "sixty-four million, five hundred forty thousand, eighty-one".