816985979 has 4 divisors (see below), whose sum is σ = 817044480. Its totient is φ = 816927480.

The previous prime is 816985973. The next prime is 816985987. The reversal of 816985979 is 979589618.

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 816985979 - 2⁸ = 816985723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (816985973) 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 in 3 ways as a sum of consecutive naturals, for example, 5309 + ... + 40769.

It is an arithmetic number, because the mean of its divisors is an integer number (204261120).

Almost surely, 2^816985979 is an apocalyptic number.

816985979 is a deficient number, since it is larger than the sum of its proper divisors (58501).

816985979 is a wasteful number, since it uses less digits than its factorization.

816985979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58500.

The product of its digits is 9797760, while the sum is 62.

The square root of 816985979 is about 28582.9665885121. The cubic root of 816985979 is about 934.8419682011.

The spelling of 816985979 in words is "eight hundred sixteen million, nine hundred eighty-five thousand, nine hundred seventy-nine".