478731991 has 2 divisors, whose sum is σ = 478731992. Its totient is φ = 478731990.

The previous prime is 478731983. The next prime is 478731997. The reversal of 478731991 is 199137874.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 478731991 - 2³ = 478731983 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (478731997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 239365995 + 239365996.

It is an arithmetic number, because the mean of its divisors is an integer number (239365996).

Almost surely, 2^478731991 is an apocalyptic number.

478731991 is a deficient number, since it is larger than the sum of its proper divisors (1).

478731991 is an equidigital number, since it uses as much as digits as its factorization.

478731991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 381024, while the sum is 49.

The square root of 478731991 is about 21879.9449496565. The cubic root of 478731991 is about 782.2834636483.

The spelling of 478731991 in words is "four hundred seventy-eight million, seven hundred thirty-one thousand, nine hundred ninety-one".