64739581 has 2 divisors, whose sum is σ = 64739582. Its totient is φ = 64739580.

The previous prime is 64739573. The next prime is 64739599. The reversal of 64739581 is 18593746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42968025 + 21771556 = 6555^2 + 4666^2 .

It is a cyclic number.

It is not a de Polignac number, because 64739581 - 2³ = 64739573 is a prime.

It is a super-2 number, since 2×64739581² = 8382426696111122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64739531) 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, 32369790 + 32369791.

It is an arithmetic number, because the mean of its divisors is an integer number (32369791).

Almost surely, 2^64739581 is an apocalyptic number.

It is an amenable number.

64739581 is a deficient number, since it is larger than the sum of its proper divisors (1).

64739581 is an equidigital number, since it uses as much as digits as its factorization.

64739581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 181440, while the sum is 43.

The square root of 64739581 is about 8046.0910385106. The cubic root of 64739581 is about 401.5348964487.

The spelling of 64739581 in words is "sixty-four million, seven hundred thirty-nine thousand, five hundred eighty-one".