66662161920 has 640 divisors, whose sum is σ = 249464033280. Its totient is φ = 16849797120.

The previous prime is 66662161879. The next prime is 66662161963. The reversal of 66662161920 is 2916126666.

It is a tau number, because it is divible by the number of its divisors (640).

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 pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 113563867 + ... + 113564453.

It is an arithmetic number, because the mean of its divisors is an integer number (389787552).

Almost surely, 2^66662161920 is an apocalyptic number.

66662161920 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 66662161920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124732016640).

66662161920 is an abundant number, since it is smaller than the sum of its proper divisors (182801871360).

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

66662161920 is a wasteful number, since it uses less digits than its factorization.

66662161920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 703 (or 681 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 45.

The spelling of 66662161920 in words is "sixty-six billion, six hundred sixty-two million, one hundred sixty-one thousand, nine hundred twenty".