77991241 has 2 divisors, whose sum is σ = 77991242. Its totient is φ = 77991240.

The previous prime is 77991239. The next prime is 77991253. The reversal of 77991241 is 14219977.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77951241 + 40000 = 8829^2 + 200^2 .

It is an emirp because it is prime and its reverse (14219977) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77991241 - 2¹ = 77991239 is a prime.

Together with 77991239, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 77991194 and 77991203.

It is not a weakly prime, because it can be changed into another prime (77991041) 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, 38995620 + 38995621.

It is an arithmetic number, because the mean of its divisors is an integer number (38995621).

Almost surely, 2^77991241 is an apocalyptic number.

It is an amenable number.

77991241 is a deficient number, since it is larger than the sum of its proper divisors (1).

77991241 is an equidigital number, since it uses as much as digits as its factorization.

77991241 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31752, while the sum is 40.

The square root of 77991241 is about 8831.2649716787. The cubic root of 77991241 is about 427.2498743158.

The spelling of 77991241 in words is "seventy-seven million, nine hundred ninety-one thousand, two hundred forty-one".