77561387 has 2 divisors, whose sum is σ = 77561388. Its totient is φ = 77561386.

The previous prime is 77561377. The next prime is 77561441. The reversal of 77561387 is 78316577.

It is a weak prime.

It is an emirp because it is prime and its reverse (78316577) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77561387 - 2⁴ = 77561371 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (77561347) 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, 38780693 + 38780694.

It is an arithmetic number, because the mean of its divisors is an integer number (38780694).

Almost surely, 2^77561387 is an apocalyptic number.

77561387 is a deficient number, since it is larger than the sum of its proper divisors (1).

77561387 is an equidigital number, since it uses as much as digits as its factorization.

77561387 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 246960, while the sum is 44.

The square root of 77561387 is about 8806.8942879996. The cubic root of 77561387 is about 426.4634889424.

The spelling of 77561387 in words is "seventy-seven million, five hundred sixty-one thousand, three hundred eighty-seven".