66320220631 has 4 divisors (see below), whose sum is σ = 75794537872. Its totient is φ = 56845903392.

The previous prime is 66320220569. The next prime is 66320220641. The reversal of 66320220631 is 13602202366.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66320220631 - 2¹¹ = 66320218583 is a prime.

It is a super-2 number, since 2×66320220631² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66320220593 and 66320220602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66320220641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4737158610 + ... + 4737158623.

It is an arithmetic number, because the mean of its divisors is an integer number (18948634468).

Almost surely, 2^66320220631 is an apocalyptic number.

66320220631 is a deficient number, since it is larger than the sum of its proper divisors (9474317241).

66320220631 is an equidigital number, since it uses as much as digits as its factorization.

66320220631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9474317240.

The product of its (nonzero) digits is 15552, while the sum is 31.

Adding to 66320220631 its reverse (13602202366), we get a palindrome (79922422997).

The spelling of 66320220631 in words is "sixty-six billion, three hundred twenty million, two hundred twenty thousand, six hundred thirty-one".