81787171227876 has 81 divisors (see below), whose sum is σ = 219618797901321. Its totient is φ = 25658430989184.

The previous prime is 81787171227863. The next prime is 81787171227919. The reversal of 81787171227876 is 67872217178718.

The square root of 81787171227876 is 9043626.

It is a perfect power (a square), and thus also a powerful number.

81787171227876 is a `hidden beast` number, since 81 + 7 + 87 + 171 + 227 + 87 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 63675133308900 + 18112037918976 = 7979670^2 + 4255824^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 922405521 + ... + 922494183.

Almost surely, 2^{81787171227876} is an apocalyptic number.

81787171227876 is the 9043626-th square number.

It is an amenable number.

81787171227876 is an abundant number, since it is smaller than the sum of its proper divisors (137831626673445).

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

81787171227876 is an frugal number, since it uses more digits than its factorization.

81787171227876 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177370 (or 88685 counting only the distinct ones).

The product of its digits is 206524416, while the sum is 72.

The spelling of 81787171227876 in words is "eighty-one trillion, seven hundred eighty-seven billion, one hundred seventy-one million, two hundred twenty-seven thousand, eight hundred seventy-six".