661773967 has 2 divisors, whose sum is σ = 661773968. Its totient is φ = 661773966.

The previous prime is 661773961. The next prime is 661774027. The reversal of 661773967 is 769377166.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661773967 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661773961) 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, 330886983 + 330886984.

It is an arithmetic number, because the mean of its divisors is an integer number (330886984).

Almost surely, 2^661773967 is an apocalyptic number.

661773967 is a deficient number, since it is larger than the sum of its proper divisors (1).

661773967 is an equidigital number, since it uses as much as digits as its factorization.

661773967 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2000376, while the sum is 52.

The square root of 661773967 is about 25724.9677745182. The cubic root of 661773967 is about 871.4381318374.

The spelling of 661773967 in words is "six hundred sixty-one million, seven hundred seventy-three thousand, nine hundred sixty-seven".