990040661 has 2 divisors, whose sum is σ = 990040662. Its totient is φ = 990040660.

The previous prime is 990040651. The next prime is 990040693. The reversal of 990040661 is 166040099.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 774508900 + 215531761 = 27830^2 + 14681^2 .

It is a cyclic number.

It is not a de Polignac number, because 990040661 - 2²² = 985846357 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (990040631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495020330 + 495020331.

It is an arithmetic number, because the mean of its divisors is an integer number (495020331).

Almost surely, 2^990040661 is an apocalyptic number.

It is an amenable number.

990040661 is a deficient number, since it is larger than the sum of its proper divisors (1).

990040661 is an equidigital number, since it uses as much as digits as its factorization.

990040661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 990040661 is about 31464.9115841758. The cubic root of 990040661 is about 996.6691380100.

The spelling of 990040661 in words is "nine hundred ninety million, forty thousand, six hundred sixty-one".