66308440320 has 288 divisors, whose sum is σ = 238217898240. Its totient is φ = 17681504256.

The previous prime is 66308440301. The next prime is 66308440337. The reversal of 66308440320 is 2304480366.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (288).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2787517 + ... + 2811203.

It is an arithmetic number, because the mean of its divisors is an integer number (827145480).

Almost surely, 2^66308440320 is an apocalyptic number.

66308440320 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 66308440320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119108949120).

66308440320 is an abundant number, since it is smaller than the sum of its proper divisors (171909457920).

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

66308440320 is an frugal number, since it uses more digits than its factorization.

66308440320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23729 (or 23697 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The spelling of 66308440320 in words is "sixty-six billion, three hundred eight million, four hundred forty thousand, three hundred twenty".