840478739 has 2 divisors, whose sum is σ = 840478740. Its totient is φ = 840478738.

The previous prime is 840478733. The next prime is 840478781. The reversal of 840478739 is 937874048.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 840478739 - 2¹² = 840474643 is a prime.

It is a super-2 number, since 2×840478739² = 1412809021422060242, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (840478733) 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, 420239369 + 420239370.

It is an arithmetic number, because the mean of its divisors is an integer number (420239370).

Almost surely, 2^840478739 is an apocalyptic number.

840478739 is a deficient number, since it is larger than the sum of its proper divisors (1).

840478739 is an equidigital number, since it uses as much as digits as its factorization.

840478739 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1354752, while the sum is 50.

The square root of 840478739 is about 28991.0113483473. The cubic root of 840478739 is about 943.7180115526.

The spelling of 840478739 in words is "eight hundred forty million, four hundred seventy-eight thousand, seven hundred thirty-nine".