771078661 has 2 divisors, whose sum is σ = 771078662. Its totient is φ = 771078660.

The previous prime is 771078641. The next prime is 771078667. The reversal of 771078661 is 166870177.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 440748036 + 330330625 = 20994^2 + 18175^2 .

It is a cyclic number.

It is not a de Polignac number, because 771078661 - 2⁷ = 771078533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (771078667) 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, 385539330 + 385539331.

It is an arithmetic number, because the mean of its divisors is an integer number (385539331).

Almost surely, 2^771078661 is an apocalyptic number.

It is an amenable number.

771078661 is a deficient number, since it is larger than the sum of its proper divisors (1).

771078661 is an equidigital number, since it uses as much as digits as its factorization.

771078661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 98784, while the sum is 43.

The square root of 771078661 is about 27768.3031710618. The cubic root of 771078661 is about 916.9934386431.

The spelling of 771078661 in words is "seven hundred seventy-one million, seventy-eight thousand, six hundred sixty-one".