816956503666 has 8 divisors (see below), whose sum is σ = 1225497756780. Its totient is φ = 408457251408.

The previous prime is 816956503633. The next prime is 816956503679. The reversal of 816956503666 is 666305659618.

It can be written as a sum of positive squares in 2 ways, for example, as 790091654641 + 26864849025 = 888871^2 + 163905^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10451541 + ... + 10529416.

Almost surely, 2^816956503666 is an apocalyptic number.

816956503666 is a deficient number, since it is larger than the sum of its proper divisors (408541253114).

816956503666 is a wasteful number, since it uses less digits than its factorization.

816956503666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21000428.

The product of its (nonzero) digits is 41990400, while the sum is 61.

The spelling of 816956503666 in words is "eight hundred sixteen billion, nine hundred fifty-six million, five hundred three thousand, six hundred sixty-six".