81510210202817 has 4 divisors (see below), whose sum is σ = 88920229312176. Its totient is φ = 74100191093460.

The previous prime is 81510210202793. The next prime is 81510210202819. The reversal of 81510210202817 is 71820201201518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81510210202817 - 2²² = 81510206008513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81510210202819) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3705009554663 + ... + 3705009554684.

It is an arithmetic number, because the mean of its divisors is an integer number (22230057328044).

Almost surely, 2^{81510210202817} is an apocalyptic number.

It is an amenable number.

81510210202817 is a deficient number, since it is larger than the sum of its proper divisors (7410019109359).

81510210202817 is a wasteful number, since it uses less digits than its factorization.

81510210202817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7410019109358.

The product of its (nonzero) digits is 17920, while the sum is 38.

The spelling of 81510210202817 in words is "eighty-one trillion, five hundred ten billion, two hundred ten million, two hundred two thousand, eight hundred seventeen".