64187861 has 2 divisors, whose sum is σ = 64187862. Its totient is φ = 64187860.

The previous prime is 64187839. The next prime is 64187881. The reversal of 64187861 is 16878146.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34692100 + 29495761 = 5890^2 + 5431^2 .

It is a cyclic number.

It is not a de Polignac number, because 64187861 - 2⁶ = 64187797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64187821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32093930 + 32093931.

It is an arithmetic number, because the mean of its divisors is an integer number (32093931).

Almost surely, 2^64187861 is an apocalyptic number.

It is an amenable number.

64187861 is a deficient number, since it is larger than the sum of its proper divisors (1).

64187861 is an equidigital number, since it uses as much as digits as its factorization.

64187861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64512, while the sum is 41.

The square root of 64187861 is about 8011.7327089713. The cubic root of 64187861 is about 400.3909947665.

The spelling of 64187861 in words is "sixty-four million, one hundred eighty-seven thousand, eight hundred sixty-one".