661349771 has 2 divisors, whose sum is σ = 661349772. Its totient is φ = 661349770.

The previous prime is 661349747. The next prime is 661349779. The reversal of 661349771 is 177943166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661349771 - 2⁶ = 661349707 is a prime.

It is not a weakly prime, because it can be changed into another prime (661349779) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330674885 + 330674886.

It is an arithmetic number, because the mean of its divisors is an integer number (330674886).

Almost surely, 2^661349771 is an apocalyptic number.

661349771 is a deficient number, since it is larger than the sum of its proper divisors (1).

661349771 is an equidigital number, since it uses as much as digits as its factorization.

661349771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 190512, while the sum is 44.

The square root of 661349771 is about 25716.7216223219. The cubic root of 661349771 is about 871.2518952469.

The spelling of 661349771 in words is "six hundred sixty-one million, three hundred forty-nine thousand, seven hundred seventy-one".