816555262566 has 32 divisors (see below), whose sum is σ = 1658110521600. Its totient is φ = 268027673760.

The previous prime is 816555262561. The next prime is 816555262577. The reversal of 816555262566 is 665262555618.

It is a super-3 number, since 3×816555262566³ (a number of 37 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816555262561) 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, 802936 + ... + 1509243.

It is an arithmetic number, because the mean of its divisors is an integer number (51815953800).

Almost surely, 2^816555262566 is an apocalyptic number.

816555262566 is an abundant number, since it is smaller than the sum of its proper divisors (841555259034).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

816555262566 is a wasteful number, since it uses less digits than its factorization.

816555262566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2313084.

The product of its digits is 25920000, while the sum is 57.

The spelling of 816555262566 in words is "eight hundred sixteen billion, five hundred fifty-five million, two hundred sixty-two thousand, five hundred sixty-six".