66220653640 has 128 divisors (see below), whose sum is σ = 160218000000. Its totient is φ = 24557285376.

The previous prime is 66220653547. The next prime is 66220653649. The reversal of 66220653640 is 4635602266.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 66220653593 and 66220653602.

It is not an unprimeable number, because it can be changed into a prime (66220653649) 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, 10265136 + ... + 10271584.

It is an arithmetic number, because the mean of its divisors is an integer number (1251703125).

Almost surely, 2^66220653640 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 66220653640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80109000000).

66220653640 is an abundant number, since it is smaller than the sum of its proper divisors (93997346360).

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

66220653640 is a wasteful number, since it uses less digits than its factorization.

66220653640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6767 (or 6763 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 40.

The spelling of 66220653640 in words is "sixty-six billion, two hundred twenty million, six hundred fifty-three thousand, six hundred forty".