77491 has 2 divisors, whose sum is σ = 77492. Its totient is φ = 77490.

The previous prime is 77489. The next prime is 77509. The reversal of 77491 is 19477.

It is a weak prime.

It is an emirp because it is prime and its reverse (19477) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77491 - 2¹ = 77489 is a prime.

Together with 77489, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (77431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38745 + 38746.

It is an arithmetic number, because the mean of its divisors is an integer number (38746).

2⁷⁷⁴⁹¹ is an apocalyptic number.

77491 is a deficient number, since it is larger than the sum of its proper divisors (1).

77491 is an equidigital number, since it uses as much as digits as its factorization.

77491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1764, while the sum is 28.

The square root of 77491 is about 278.3720531950. The cubic root of 77491 is about 42.6334444617.

It can be divided in two parts, 7749 and 1, that added together give a triangular number (7750 = T₁₂₄).

The spelling of 77491 in words is "seventy-seven thousand, four hundred ninety-one".