66161011556 has 12 divisors (see below), whose sum is σ = 115869426540. Its totient is φ = 33055461120.

The previous prime is 66161011547. The next prime is 66161011573. The reversal of 66161011556 is 65511016166.

It can be written as a sum of positive squares in 2 ways, for example, as 61115750656 + 5045260900 = 247216^2 + 71030^2 .

It is a super-2 number, since 2×66161011556² (a number of 22 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6255221 + ... + 6265788.

It is an arithmetic number, because the mean of its divisors is an integer number (9655785545).

Almost surely, 2^66161011556 is an apocalyptic number.

It is an amenable number.

66161011556 is a deficient number, since it is larger than the sum of its proper divisors (49708414984).

66161011556 is a wasteful number, since it uses less digits than its factorization.

66161011556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12522334 (or 12522332 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 38.

The spelling of 66161011556 in words is "sixty-six billion, one hundred sixty-one million, eleven thousand, five hundred fifty-six".