813978499 has 2 divisors, whose sum is σ = 813978500. Its totient is φ = 813978498.

The previous prime is 813978497. The next prime is 813978509. The reversal of 813978499 is 994879318.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 813978499 - 2¹ = 813978497 is a prime.

Together with 813978497, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (813978497) 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, 406989249 + 406989250.

It is an arithmetic number, because the mean of its divisors is an integer number (406989250).

Almost surely, 2^813978499 is an apocalyptic number.

813978499 is a deficient number, since it is larger than the sum of its proper divisors (1).

813978499 is an equidigital number, since it uses as much as digits as its factorization.

813978499 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3919104, while the sum is 58.

The square root of 813978499 is about 28530.3084280559. The cubic root of 813978499 is about 933.6934476723.

The spelling of 813978499 in words is "eight hundred thirteen million, nine hundred seventy-eight thousand, four hundred ninety-nine".