66275987640 has 128 divisors (see below), whose sum is σ = 208240588800. Its totient is φ = 16842608640.

The previous prime is 66275987629. The next prime is 66275987647. The reversal of 66275987640 is 4678957266.

It is a Smith number, since the sum of its digits (60) 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 (60).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66275987647) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 703656 + ... + 792264.

It is an arithmetic number, because the mean of its divisors is an integer number (1626879600).

Almost surely, 2^66275987640 is an apocalyptic number.

66275987640 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 66275987640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104120294400).

66275987640 is an abundant number, since it is smaller than the sum of its proper divisors (141964601160).

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

66275987640 is a wasteful number, since it uses less digits than its factorization.

66275987640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88917 (or 88913 counting only the distinct ones).

The product of its (nonzero) digits is 30481920, while the sum is 60.

The spelling of 66275987640 in words is "sixty-six billion, two hundred seventy-five million, nine hundred eighty-seven thousand, six hundred forty".