64391281 has 4 divisors (see below), whose sum is σ = 66611700. Its totient is φ = 62170864.

The previous prime is 64391263. The next prime is 64391311. The reversal of 64391281 is 18219346.

64391281 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 54997056 + 9394225 = 7416^2 + 3065^2 .

It is a cyclic number.

It is not a de Polignac number, because 64391281 - 2¹⁹ = 63866993 is a prime.

It is a super-2 number, since 2×64391281² = 8292474137641922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64398281) 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 3 ways as a sum of consecutive naturals, for example, 1110166 + ... + 1110223.

It is an arithmetic number, because the mean of its divisors is an integer number (16652925).

Almost surely, 2^64391281 is an apocalyptic number.

It is an amenable number.

64391281 is a deficient number, since it is larger than the sum of its proper divisors (2220419).

64391281 is a wasteful number, since it uses less digits than its factorization.

64391281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2220418.

The product of its digits is 10368, while the sum is 34.

The square root of 64391281 is about 8024.4177981957. The cubic root of 64391281 is about 400.8135131194.

The spelling of 64391281 in words is "sixty-four million, three hundred ninety-one thousand, two hundred eighty-one".