661383959 has 2 divisors, whose sum is σ = 661383960. Its totient is φ = 661383958.

The previous prime is 661383949. The next prime is 661384019. The reversal of 661383959 is 959383166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661383959 - 2¹⁶ = 661318423 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661383949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330691979 + 330691980.

It is an arithmetic number, because the mean of its divisors is an integer number (330691980).

Almost surely, 2^661383959 is an apocalyptic number.

661383959 is a deficient number, since it is larger than the sum of its proper divisors (1).

661383959 is an equidigital number, since it uses as much as digits as its factorization.

661383959 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1049760, while the sum is 50.

The square root of 661383959 is about 25717.3863174312. The cubic root of 661383959 is about 871.2669079012.

The spelling of 661383959 in words is "six hundred sixty-one million, three hundred eighty-three thousand, nine hundred fifty-nine".