64636381 has 2 divisors, whose sum is σ = 64636382. Its totient is φ = 64636380.

The previous prime is 64636357. The next prime is 64636387. The reversal of 64636381 is 18363646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 36905625 + 27730756 = 6075^2 + 5266^2 .

It is a cyclic number.

It is not a de Polignac number, because 64636381 - 2⁹ = 64635869 is a prime.

It is a super-2 number, since 2×64636381² = 8355723497554322, 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 64636381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64636387) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32318190 + 32318191.

It is an arithmetic number, because the mean of its divisors is an integer number (32318191).

Almost surely, 2^64636381 is an apocalyptic number.

It is an amenable number.

64636381 is a deficient number, since it is larger than the sum of its proper divisors (1).

64636381 is an equidigital number, since it uses as much as digits as its factorization.

64636381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 62208, while the sum is 37.

The square root of 64636381 is about 8039.6754287720. The cubic root of 64636381 is about 401.3214235424.

The spelling of 64636381 in words is "sixty-four million, six hundred thirty-six thousand, three hundred eighty-one".