77725861 has 2 divisors, whose sum is σ = 77725862. Its totient is φ = 77725860.

The previous prime is 77725849. The next prime is 77725867. The reversal of 77725861 is 16852777.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76300225 + 1425636 = 8735^2 + 1194^2 .

It is a cyclic number.

It is not a de Polignac number, because 77725861 - 2¹⁷ = 77594789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77725867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38862930 + 38862931.

It is an arithmetic number, because the mean of its divisors is an integer number (38862931).

Almost surely, 2^77725861 is an apocalyptic number.

It is an amenable number.

77725861 is a deficient number, since it is larger than the sum of its proper divisors (1).

77725861 is an equidigital number, since it uses as much as digits as its factorization.

77725861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 164640, while the sum is 43.

The square root of 77725861 is about 8816.2271409033. The cubic root of 77725861 is about 426.7647240310.

The spelling of 77725861 in words is "seventy-seven million, seven hundred twenty-five thousand, eight hundred sixty-one".