666722288881 has 24 divisors (see below), whose sum is σ = 758151158184. Its totient is φ = 585472800000.

The previous prime is 666722288861. The next prime is 666722288891. The reversal of 666722288881 is 188882227666.

It can be written as a sum of positive squares in 4 ways, for example, as 20587658256 + 646134630625 = 143484^2 + 803825^2 .

It is not a de Polignac number, because 666722288881 - 2¹³ = 666722280689 is a prime.

It is a super-2 number, since 2×666722288881² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666722288861) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 164250 + ... + 1166371.

It is an arithmetic number, because the mean of its divisors is an integer number (31589631591).

Almost surely, 2^666722288881 is an apocalyptic number.

It is an amenable number.

666722288881 is a deficient number, since it is larger than the sum of its proper divisors (91428869303).

666722288881 is a wasteful number, since it uses less digits than its factorization.

666722288881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1330785 (or 1330774 counting only the distinct ones).

The product of its digits is 49545216, while the sum is 64.

The spelling of 666722288881 in words is "six hundred sixty-six billion, seven hundred twenty-two million, two hundred eighty-eight thousand, eight hundred eighty-one".