64557523685 has 4 divisors (see below), whose sum is σ = 77469028428. Its totient is φ = 51646018944.

The previous prime is 64557523673. The next prime is 64557523697. The reversal of 64557523685 is 58632575546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58632575546 = 2 ⋅29316287773.

It is an interprime number because it is at equal distance from previous prime (64557523673) and next prime (64557523697).

It can be written as a sum of positive squares in 2 ways, for example, as 12900870724 + 51656652961 = 113582^2 + 227281^2 .

It is a cyclic number.

It is not a de Polignac number, because 64557523685 - 2⁶ = 64557523621 is a prime.

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 64557523685.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6455752364 + ... + 6455752373.

It is an arithmetic number, because the mean of its divisors is an integer number (19367257107).

Almost surely, 2^64557523685 is an apocalyptic number.

It is an amenable number.

64557523685 is a deficient number, since it is larger than the sum of its proper divisors (12911504743).

64557523685 is a wasteful number, since it uses less digits than its factorization.

64557523685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12911504742.

The product of its digits is 30240000, while the sum is 56.

The spelling of 64557523685 in words is "sixty-four billion, five hundred fifty-seven million, five hundred twenty-three thousand, six hundred eighty-five".