816506121 has 8 divisors (see below), whose sum is σ = 1118098624. Its totient is φ = 529625520.

The previous prime is 816506087. The next prime is 816506123. The reversal of 816506121 is 121605618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 816506121 - 2¹⁸ = 816243977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (816506123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3677845 + ... + 3678066.

It is an arithmetic number, because the mean of its divisors is an integer number (139762328).

Almost surely, 2^816506121 is an apocalyptic number.

It is an amenable number.

816506121 is a deficient number, since it is larger than the sum of its proper divisors (301592503).

816506121 is a wasteful number, since it uses less digits than its factorization.

816506121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7355951.

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 816506121 is about 28574.5712303789. The cubic root of 816506121 is about 934.6589053888.

The spelling of 816506121 in words is "eight hundred sixteen million, five hundred six thousand, one hundred twenty-one".