1555655666 has 16 divisors (see below), whose sum is σ = 2479260960. Its totient is φ = 730000800.

The previous prime is 1555655663. The next prime is 1555655681. The reversal of 1555655666 is 6665565551.

It is not an unprimeable number, because it can be changed into a prime (1555655663) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 187235 + ... + 195366.

It is an arithmetic number, because the mean of its divisors is an integer number (154953810).

Almost surely, 2^1555655666 is an apocalyptic number.

1555655666 is a deficient number, since it is larger than the sum of its proper divisors (923605294).

1555655666 is a wasteful number, since it uses less digits than its factorization.

1555655666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 382729.

The product of its digits is 4050000, while the sum is 50.

The square root of 1555655666 is about 39441.8009984331. The cubic root of 1555655666 is about 1158.7004039460.

The spelling of 1555655666 in words is "one billion, five hundred fifty-five million, six hundred fifty-five thousand, six hundred sixty-six".