999431 has 2 divisors, whose sum is σ = 999432. Its totient is φ = 999430.

The previous prime is 999389. The next prime is 999433. The reversal of 999431 is 134999.

It is a strong prime.

It is an emirp because it is prime and its reverse (134999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999431 - 2¹⁸ = 737287 is a prime.

It is a super-2 number, since 2×999431² = 1997724647522, which contains 22 as substring.

Together with 999433, it forms a pair of twin primes.

It is a Chen prime.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 999391 and 999400.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499715 + 499716.

It is an arithmetic number, because the mean of its divisors is an integer number (499716).

2⁹⁹⁹⁴³¹ is an apocalyptic number.

999431 is a deficient number, since it is larger than the sum of its proper divisors (1).

999431 is an equidigital number, since it uses as much as digits as its factorization.

999431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8748, while the sum is 35.

The square root of 999431 is about 999.7154595184. The cubic root of 999431 is about 99.9810297349.

The spelling of 999431 in words is "nine hundred ninety-nine thousand, four hundred thirty-one".