64890572785 has 4 divisors (see below), whose sum is σ = 77868687348. Its totient is φ = 51912458224.

The previous prime is 64890572749. The next prime is 64890572837. The reversal of 64890572785 is 58727509846.

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 13102923024 + 51787649761 = 114468^2 + 227569^2 .

It is a cyclic number.

It is not a de Polignac number, because 64890572785 - 2¹³ = 64890564593 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6489057274 + ... + 6489057283.

It is an arithmetic number, because the mean of its divisors is an integer number (19467171837).

Almost surely, 2^64890572785 is an apocalyptic number.

It is an amenable number.

64890572785 is a deficient number, since it is larger than the sum of its proper divisors (12978114563).

64890572785 is a wasteful number, since it uses less digits than its factorization.

64890572785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12978114562.

The product of its (nonzero) digits is 33868800, while the sum is 61.

The spelling of 64890572785 in words is "sixty-four billion, eight hundred ninety million, five hundred seventy-two thousand, seven hundred eighty-five".