661376741 has 2 divisors, whose sum is σ = 661376742. Its totient is φ = 661376740.

The previous prime is 661376731. The next prime is 661376743. The reversal of 661376741 is 147673166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 541911841 + 119464900 = 23279^2 + 10930^2 .

It is a cyclic number.

It is not a de Polignac number, because 661376741 - 2¹⁰ = 661375717 is a prime.

Together with 661376743, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661376743) 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, 330688370 + 330688371.

It is an arithmetic number, because the mean of its divisors is an integer number (330688371).

Almost surely, 2^661376741 is an apocalyptic number.

It is an amenable number.

661376741 is a deficient number, since it is larger than the sum of its proper divisors (1).

661376741 is an equidigital number, since it uses as much as digits as its factorization.

661376741 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 127008, while the sum is 41.

The square root of 661376741 is about 25717.2459839696. The cubic root of 661376741 is about 871.2637383720.

The spelling of 661376741 in words is "six hundred sixty-one million, three hundred seventy-six thousand, seven hundred forty-one".