81238546197 has 12 divisors (see below), whose sum is σ = 117354526380. Its totient is φ = 54154434048.

The previous prime is 81238546139. The next prime is 81238546211. The reversal of 81238546197 is 79164583218.

81238546197 is a `hidden beast` number, since 8 + 1 + 2 + 3 + 8 + 546 + 1 + 97 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 6376661316 + 74861884881 = 79854^2 + 273609^2 .

It is not a de Polignac number, because 81238546197 - 2¹⁰ = 81238545173 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81238544197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 269358 + ... + 484799.

It is an arithmetic number, because the mean of its divisors is an integer number (9779543865).

Almost surely, 2^81238546197 is an apocalyptic number.

It is an amenable number.

81238546197 is a deficient number, since it is larger than the sum of its proper divisors (36115980183).

81238546197 is a wasteful number, since it uses less digits than its factorization.

81238546197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 766132 (or 766129 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 54.

The spelling of 81238546197 in words is "eighty-one billion, two hundred thirty-eight million, five hundred forty-six thousand, one hundred ninety-seven".