1006665561 has 48 divisors (see below), whose sum is σ = 1642006080. Its totient is φ = 588994560.

The previous prime is 1006665551. The next prime is 1006665563. The reversal of 1006665561 is 1655666001.

1006665561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1006665561 - 2⁵ = 1006665529 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1006665563) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 377545 + ... + 380201.

It is an arithmetic number, because the mean of its divisors is an integer number (34208460).

Almost surely, 2^1006665561 is an apocalyptic number.

1006665561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1006665561 is a deficient number, since it is larger than the sum of its proper divisors (635340519).

1006665561 is a wasteful number, since it uses less digits than its factorization.

1006665561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2806 (or 2803 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 1006665561 is about 31727.9933339630. The cubic root of 1006665561 is about 1002.2169352329.

The spelling of 1006665561 in words is "one billion, six million, six hundred sixty-five thousand, five hundred sixty-one".