816520243 has 16 divisors (see below), whose sum is σ = 1027892736. Its totient is φ = 630066240.

The previous prime is 816520213. The next prime is 816520273. The reversal of 816520243 is 342025618.

It is an interprime number because it is at equal distance from previous prime (816520213) and next prime (816520273).

It is a cyclic number.

It is not a de Polignac number, because 816520243 - 2²¹ = 814423091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (816520213) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43546 + ... + 59407.

It is an arithmetic number, because the mean of its divisors is an integer number (64243296).

Almost surely, 2^816520243 is an apocalyptic number.

816520243 is a deficient number, since it is larger than the sum of its proper divisors (211372493).

816520243 is a wasteful number, since it uses less digits than its factorization.

816520243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103074.

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 816520243 is about 28574.8183371303. The cubic root of 816520243 is about 934.6642938672.

The spelling of 816520243 in words is "eight hundred sixteen million, five hundred twenty thousand, two hundred forty-three".