66681481632 has 96 divisors (see below), whose sum is σ = 185433494400. Its totient is φ = 20908597248.

The previous prime is 66681481627. The next prime is 66681481637. The reversal of 66681481632 is 23618418666.

It is an interprime number because it is at equal distance from previous prime (66681481627) and next prime (66681481637).

It is a tau number, because it is divible by the number of its divisors (96).

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

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (66681481637) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3399469 + ... + 3419027.

It is an arithmetic number, because the mean of its divisors is an integer number (1931598900).

Almost surely, 2^66681481632 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66681481632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92716747200).

66681481632 is an abundant number, since it is smaller than the sum of its proper divisors (118752012768).

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

66681481632 is a wasteful number, since it uses less digits than its factorization.

66681481632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21678 (or 21670 counting only the distinct ones).

The product of its digits is 1990656, while the sum is 51.

The spelling of 66681481632 in words is "sixty-six billion, six hundred eighty-one million, four hundred eighty-one thousand, six hundred thirty-two".