77609681 has 2 divisors, whose sum is σ = 77609682. Its totient is φ = 77609680.

The previous prime is 77609669. The next prime is 77609689. The reversal of 77609681 is 18690677.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70896400 + 6713281 = 8420^2 + 2591^2 .

It is a cyclic number.

It is not a de Polignac number, because 77609681 - 2⁶ = 77609617 is a prime.

It is a super-2 number, since 2×77609681² = 12046525169843522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (77609689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38804840 + 38804841.

It is an arithmetic number, because the mean of its divisors is an integer number (38804841).

Almost surely, 2^77609681 is an apocalyptic number.

It is an amenable number.

77609681 is a deficient number, since it is larger than the sum of its proper divisors (1).

77609681 is an equidigital number, since it uses as much as digits as its factorization.

77609681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 127008, while the sum is 44.

The square root of 77609681 is about 8809.6356905379. The cubic root of 77609681 is about 426.5519838123.

The spelling of 77609681 in words is "seventy-seven million, six hundred nine thousand, six hundred eighty-one".