66398955752880 has 1600 divisors, whose sum is σ = 260918590141440. Its totient is φ = 15568522444800.

The previous prime is 66398955752873. The next prime is 66398955752917. The reversal of 66398955752880 is 8825755989366.

It is a happy number.

66398955752880 is a `hidden beast` number, since 6 + 6 + 3 + 9 + 8 + 9 + 5 + 5 + 7 + 528 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a self number, because there is not a number n which added to its sum of digits gives 66398955752880.

It is an unprimeable number.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 13581293476 + ... + 13581298364.

Almost surely, 2^{66398955752880} is an apocalyptic number.

66398955752880 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 66398955752880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130459295070720).

66398955752880 is an abundant number, since it is smaller than the sum of its proper divisors (194519634388560).

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

66398955752880 is a wasteful number, since it uses less digits than its factorization.

66398955752880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5100 (or 5085 counting only the distinct ones).

The product of its (nonzero) digits is 7838208000, while the sum is 81.

The spelling of 66398955752880 in words is "sixty-six trillion, three hundred ninety-eight billion, nine hundred fifty-five million, seven hundred fifty-two thousand, eight hundred eighty".