64538181 has 24 divisors (see below), whose sum is σ = 97090560. Its totient is φ = 42369912.

The previous prime is 64538179. The next prime is 64538203. The reversal of 64538181 is 18183546.

64538181 is a `hidden beast` number, since 645 + 3 + 8 + 1 + 8 + 1 = 666.

64538181 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 64538181 - 2¹ = 64538179 is a prime.

It is a super-2 number, since 2×64538181² = 8330353613577522, which contains 22 as substring.

64538181 is a modest number, since divided by 8181 gives 6453 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64538081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 168316 + ... + 168698.

It is an arithmetic number, because the mean of its divisors is an integer number (4045440).

Almost surely, 2^64538181 is an apocalyptic number.

It is an amenable number.

64538181 is a deficient number, since it is larger than the sum of its proper divisors (32552379).

64538181 is an equidigital number, since it uses as much as digits as its factorization.

64538181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 550 (or 465 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 64538181 is about 8033.5658956655. The cubic root of 64538181 is about 401.1180822350.

The spelling of 64538181 in words is "sixty-four million, five hundred thirty-eight thousand, one hundred eighty-one".