81690802265 has 8 divisors (see below), whose sum is σ = 98031382920. Its totient is φ = 65351028352.

The previous prime is 81690802261. The next prime is 81690802283. The reversal of 81690802265 is 56220809618.

It can be written as a sum of positive squares in 4 ways, for example, as 42428172361 + 39262629904 = 205981^2 + 198148^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 81690802265 - 2² = 81690802261 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81690802261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49541 + ... + 407229.

It is an arithmetic number, because the mean of its divisors is an integer number (12253922865).

Almost surely, 2^81690802265 is an apocalyptic number.

It is an amenable number.

81690802265 is a deficient number, since it is larger than the sum of its proper divisors (16340580655).

81690802265 is a wasteful number, since it uses less digits than its factorization.

81690802265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403371.

The product of its (nonzero) digits is 414720, while the sum is 47.

The spelling of 81690802265 in words is "eighty-one billion, six hundred ninety million, eight hundred two thousand, two hundred sixty-five".