816616615537 has 2 divisors, whose sum is σ = 816616615538. Its totient is φ = 816616615536.

The previous prime is 816616615523. The next prime is 816616615603. The reversal of 816616615537 is 735516616618.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 761624489521 + 54992126016 = 872711^2 + 234504^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-816616615537 is a prime.

It is a super-2 number, since 2×816616615537² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (816616619537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408308307768 + 408308307769.

It is an arithmetic number, because the mean of its divisors is an integer number (408308307769).

Almost surely, 2^816616615537 is an apocalyptic number.

It is an amenable number.

816616615537 is a deficient number, since it is larger than the sum of its proper divisors (1).

816616615537 is an equidigital number, since it uses as much as digits as its factorization.

816616615537 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5443200, while the sum is 55.

The spelling of 816616615537 in words is "eight hundred sixteen billion, six hundred sixteen million, six hundred fifteen thousand, five hundred thirty-seven".