66501821880 has 512 divisors, whose sum is σ = 251693568000. Its totient is φ = 15495321600.

The previous prime is 66501821879. The next prime is 66501821927. The reversal of 66501821880 is 8812810566.

66501821880 is a `hidden beast` number, since 66 + 501 + 8 + 2 + 1 + 8 + 80 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 32613901 + ... + 32615939.

It is an arithmetic number, because the mean of its divisors is an integer number (491589000).

Almost surely, 2^66501821880 is an apocalyptic number.

66501821880 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 66501821880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125846784000).

66501821880 is an abundant number, since it is smaller than the sum of its proper divisors (185191746120).

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

66501821880 is a wasteful number, since it uses less digits than its factorization.

66501821880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2196 (or 2186 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 45.

The spelling of 66501821880 in words is "sixty-six billion, five hundred one million, eight hundred twenty-one thousand, eight hundred eighty".