1166550556561 has 16 divisors (see below), whose sum is σ = 1261315972224. Its totient is φ = 1072505476224.

The previous prime is 1166550556543. The next prime is 1166550556583. The reversal of 1166550556561 is 1656550556611.

It is not a de Polignac number, because 1166550556561 - 2¹⁹ = 1166550032273 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1166550556499 and 1166550556508.

It is not an unprimeable number, because it can be changed into a prime (1166550586561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18386485 + ... + 18449821.

It is an arithmetic number, because the mean of its divisors is an integer number (78832248264).

Almost surely, 2^{1166550556561} is an apocalyptic number.

It is an amenable number.

1166550556561 is a deficient number, since it is larger than the sum of its proper divisors (94765415663).

1166550556561 is a wasteful number, since it uses less digits than its factorization.

1166550556561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69000.

The product of its (nonzero) digits is 4050000, while the sum is 52.

The spelling of 1166550556561 in words is "one trillion, one hundred sixty-six billion, five hundred fifty million, five hundred fifty-six thousand, five hundred sixty-one".