64065781 has 8 divisors (see below), whose sum is σ = 69181280. Its totient is φ = 58977072.

The previous prime is 64065769. The next prime is 64065797. The reversal of 64065781 is 18756046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 64065781 - 2¹⁹ = 63541493 is a prime.

It is a super-2 number, since 2×64065781² = 8208848590279922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64065781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64065751) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1575 + ... + 11428.

It is an arithmetic number, because the mean of its divisors is an integer number (8647660).

Almost surely, 2^64065781 is an apocalyptic number.

It is an amenable number.

64065781 is a deficient number, since it is larger than the sum of its proper divisors (5115499).

64065781 is a wasteful number, since it uses less digits than its factorization.

64065781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13395.

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 64065781 is about 8004.1102566119. The cubic root of 64065781 is about 400.1369968243.

It can be divided in two parts, 64065 and 781, that added together give a palindrome (64846).

The spelling of 64065781 in words is "sixty-four million, sixty-five thousand, seven hundred eighty-one".