78431 has 4 divisors (see below), whose sum is σ = 79272. Its totient is φ = 77592.

The previous prime is 78427. The next prime is 78437. The reversal of 78431 is 13487.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 78431 - 2² = 78427 is a prime.

It is a super-2 number, since 2×78431² = 12302843522, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 78397 and 78406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78437) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 260 + ... + 473.

It is an arithmetic number, because the mean of its divisors is an integer number (19818).

2⁷⁸⁴³¹ is an apocalyptic number.

78431 is a deficient number, since it is larger than the sum of its proper divisors (841).

78431 is a wasteful number, since it uses less digits than its factorization.

78431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840.

The product of its digits is 672, while the sum is 23.

The square root of 78431 is about 280.0553516718. The cubic root of 78431 is about 42.8051395697.

The spelling of 78431 in words is "seventy-eight thousand, four hundred thirty-one".