66519891600 has 240 divisors, whose sum is σ = 235431038592. Its totient is φ = 15969198080.

The previous prime is 66519891593. The next prime is 66519891629. The reversal of 66519891600 is 619891566.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (51).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 398314 + ... + 540086.

Almost surely, 2^66519891600 is an apocalyptic number.

66519891600 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 66519891600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117715519296).

66519891600 is an abundant number, since it is smaller than the sum of its proper divisors (168911146992).

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

66519891600 is a wasteful number, since it uses less digits than its factorization.

66519891600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141834 (or 141823 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 51.

The spelling of 66519891600 in words is "sixty-six billion, five hundred nineteen million, eight hundred ninety-one thousand, six hundred".