81171827051 has 16 divisors (see below), whose sum is σ = 97925208000. Its totient is φ = 67176676224.

The previous prime is 81171827039. The next prime is 81171827063. The reversal of 81171827051 is 15072817118.

It is an interprime number because it is at equal distance from previous prime (81171827039) and next prime (81171827063).

It is not a de Polignac number, because 81171827051 - 2¹⁸ = 81171564907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81171827251) 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, 4070270 + ... + 4090163.

It is an arithmetic number, because the mean of its divisors is an integer number (6120325500).

Almost surely, 2^81171827051 is an apocalyptic number.

81171827051 is a deficient number, since it is larger than the sum of its proper divisors (16753380949).

81171827051 is an equidigital number, since it uses as much as digits as its factorization.

81171827051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8160483 (or 8160469 counting only the distinct ones).

The product of its (nonzero) digits is 31360, while the sum is 41.

The spelling of 81171827051 in words is "eighty-one billion, one hundred seventy-one million, eight hundred twenty-seven thousand, fifty-one".