661000999 has 2 divisors, whose sum is σ = 661001000. Its totient is φ = 661000998.

The previous prime is 661000969. The next prime is 661001027. The reversal of 661000999 is 999000166.

661000999 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661000999 - 2¹¹ = 660998951 is a prime.

661000999 is a modest number, since divided by 999 gives 661 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661000909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330500499 + 330500500.

It is an arithmetic number, because the mean of its divisors is an integer number (330500500).

Almost surely, 2^661000999 is an apocalyptic number.

661000999 is a deficient number, since it is larger than the sum of its proper divisors (1).

661000999 is an equidigital number, since it uses as much as digits as its factorization.

661000999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26244, while the sum is 40.

The square root of 661000999 is about 25709.9396926558. The cubic root of 661000999 is about 871.0987127146.

The spelling of 661000999 in words is "six hundred sixty-one million, nine hundred ninety-nine", and thus it is an aban number.