65639769856 has 72 divisors (see below), whose sum is σ = 135316560960. Its totient is φ = 31760154624.

The previous prime is 65639769823. The next prime is 65639769859. The reversal of 65639769856 is 65896793656.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65639769859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1040200 + ... + 1101496.

It is an arithmetic number, because the mean of its divisors is an integer number (1879396680).

Almost surely, 2^65639769856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65639769856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67658280480).

65639769856 is an abundant number, since it is smaller than the sum of its proper divisors (69676791104).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

65639769856 is an equidigital number, since it uses as much as digits as its factorization.

65639769856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61449 (or 61435 counting only the distinct ones).

The product of its digits is 440899200, while the sum is 70.

The spelling of 65639769856 in words is "sixty-five billion, six hundred thirty-nine million, seven hundred sixty-nine thousand, eight hundred fifty-six".