64618381 has 2 divisors, whose sum is σ = 64618382. Its totient is φ = 64618380.

The previous prime is 64618327. The next prime is 64618399. The reversal of 64618381 is 18381646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 38862756 + 25755625 = 6234^2 + 5075^2 .

It is a cyclic number.

It is not a de Polignac number, because 64618381 - 2⁹ = 64617869 is a prime.

It is a super-2 number, since 2×64618381² = 8351070326122322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 64618381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64618321) 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 as a sum of consecutive naturals, namely, 32309190 + 32309191.

It is an arithmetic number, because the mean of its divisors is an integer number (32309191).

Almost surely, 2^64618381 is an apocalyptic number.

It is an amenable number.

64618381 is a deficient number, since it is larger than the sum of its proper divisors (1).

64618381 is an equidigital number, since it uses as much as digits as its factorization.

64618381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 37.

The square root of 64618381 is about 8038.5559026482. Note that the first 3 decimals coincide. The cubic root of 64618381 is about 401.2841666283.

The spelling of 64618381 in words is "sixty-four million, six hundred eighteen thousand, three hundred eighty-one".