65991088800 has 2160 divisors, whose sum is σ = 322686346752. Its totient is φ = 12765081600.

The previous prime is 65991088783. The next prime is 65991088811. The reversal of 65991088800 is 888019956.

It is a tau number, because it is divible by the number of its divisors (2160).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 359 ways as a sum of consecutive naturals, for example, 2128744785 + ... + 2128744815.

Almost surely, 2^65991088800 is an apocalyptic number.

65991088800 is a gapful number since it is divisible by the number (60) 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 65991088800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (161343173376).

65991088800 is an abundant number, since it is smaller than the sum of its proper divisors (256695257952).

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

65991088800 is a wasteful number, since it uses less digits than its factorization.

65991088800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121 (or 80 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 54.

The spelling of 65991088800 in words is "sixty-five billion, nine hundred ninety-one million, eighty-eight thousand, eight hundred".