1005386661 has 20 divisors (see below), whose sum is σ = 1503692652. Its totient is φ = 669446208.

The previous prime is 1005386639. The next prime is 1005386717. The reversal of 1005386661 is 1666835001.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 630964161 + 374422500 = 25119^2 + 19350^2 .

It is not a de Polignac number, because 1005386661 - 2¹⁴ = 1005370277 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1005386611) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 63961 + ... + 78113.

Almost surely, 2^1005386661 is an apocalyptic number.

It is an amenable number.

1005386661 is a deficient number, since it is larger than the sum of its proper divisors (498305991).

1005386661 is an equidigital number, since it uses as much as digits as its factorization.

1005386661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15042 (or 15033 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 1005386661 is about 31707.8328020065. The cubic root of 1005386661 is about 1001.7923392673.

The spelling of 1005386661 in words is "one billion, five million, three hundred eighty-six thousand, six hundred sixty-one".