77431 has 2 divisors, whose sum is σ = 77432. Its totient is φ = 77430.

The previous prime is 77419. The next prime is 77447. The reversal of 77431 is 13477.

It is a weak prime.

It is an emirp because it is prime and its reverse (13477) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77431 - 2⁹ = 76919 is a prime.

It is a super-2 number, since 2×77431² = 11991119522, which contains 22 as substring.

77431 is a lucky number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77471) 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, 38715 + 38716.

It is an arithmetic number, because the mean of its divisors is an integer number (38716).

2⁷⁷⁴³¹ is an apocalyptic number.

77431 is a deficient number, since it is larger than the sum of its proper divisors (1).

77431 is an equidigital number, since it uses as much as digits as its factorization.

77431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 588, while the sum is 22.

The square root of 77431 is about 278.2642628869. The cubic root of 77431 is about 42.6224381636.

It can be divided in two parts, 7743 and 1, that added together give a square (7744 = 88²).

The spelling of 77431 in words is "seventy-seven thousand, four hundred thirty-one".