65999855899956 has 384 divisors, whose sum is σ = 186685316923392. Its totient is φ = 17931938112000.

The previous prime is 65999855899949. The next prime is 65999855900057.

65999855899956 is nontrivially palindromic in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 776508621 + ... + 776593611.

It is an arithmetic number, because the mean of its divisors is an integer number (486159679488).

Almost surely, 2^{65999855899956} is an apocalyptic number.

65999855899956 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65999855899956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93342658461696).

65999855899956 is an abundant number, since it is smaller than the sum of its proper divisors (120685461023436).

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

65999855899956 is a wasteful number, since it uses less digits than its factorization.

65999855899956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85323 (or 85321 counting only the distinct ones).

The product of its digits is 765275040000, while the sum is 102.

The spelling of 65999855899956 in words is "sixty-five trillion, nine hundred ninety-nine billion, eight hundred fifty-five million, eight hundred ninety-nine thousand, nine hundred fifty-six".