816565501 has 2 divisors, whose sum is σ = 816565502. Its totient is φ = 816565500.

The previous prime is 816565457. The next prime is 816565531. The reversal of 816565501 is 105565618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 523265625 + 293299876 = 22875^2 + 17126^2 .

It is a cyclic number.

It is not a de Polignac number, because 816565501 - 2¹³ = 816557309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (816565531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408282750 + 408282751.

It is an arithmetic number, because the mean of its divisors is an integer number (408282751).

Almost surely, 2^816565501 is an apocalyptic number.

It is an amenable number.

816565501 is a deficient number, since it is larger than the sum of its proper divisors (1).

816565501 is an equidigital number, since it uses as much as digits as its factorization.

816565501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36000, while the sum is 37.

The square root of 816565501 is about 28575.6102472021. The cubic root of 816565501 is about 934.6815623736.

The spelling of 816565501 in words is "eight hundred sixteen million, five hundred sixty-five thousand, five hundred one".