1661544555 has 32 divisors (see below), whose sum is σ = 3070752768. Its totient is φ = 758208000.

The previous prime is 1661544529. The next prime is 1661544559. The reversal of 1661544555 is 5554451661.

It is not a de Polignac number, because 1661544555 - 2⁵ = 1661544523 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1661544559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 293371 + ... + 298980.

It is an arithmetic number, because the mean of its divisors is an integer number (95961024).

Almost surely, 2^1661544555 is an apocalyptic number.

1661544555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1661544555 is a deficient number, since it is larger than the sum of its proper divisors (1409208213).

1661544555 is a wasteful number, since it uses less digits than its factorization.

1661544555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 592387.

The product of its digits is 360000, while the sum is 42.

The square root of 1661544555 is about 40762.0479735746. The cubic root of 1661544555 is about 1184.4152681384.

The spelling of 1661544555 in words is "one billion, six hundred sixty-one million, five hundred forty-four thousand, five hundred fifty-five".