1155661666 has 16 divisors (see below), whose sum is σ = 1842618456. Its totient is φ = 541720576.

The previous prime is 1155661621. The next prime is 1155661693. The reversal of 1155661666 is 6661665511.

It can be written as a sum of positive squares in 4 ways, for example, as 1014741025 + 140920641 = 31855^2 + 11871^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57391 + ... + 74866.

Almost surely, 2^1155661666 is an apocalyptic number.

1155661666 is a deficient number, since it is larger than the sum of its proper divisors (686956790).

1155661666 is a wasteful number, since it uses less digits than its factorization.

1155661666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132533.

The product of its digits is 194400, while the sum is 43.

The square root of 1155661666 is about 33995.0241358938. The cubic root of 1155661666 is about 1049.4060634962.

The spelling of 1155661666 in words is "one billion, one hundred fifty-five million, six hundred sixty-one thousand, six hundred sixty-six".