81978112097 has 32 divisors (see below), whose sum is σ = 97378053120. Its totient is φ = 67556321280.

The previous prime is 81978112081. The next prime is 81978112129. The reversal of 81978112097 is 79021187918.

It is not a de Polignac number, because 81978112097 - 2⁴ = 81978112081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81978112597) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18641903 + ... + 18646299.

It is an arithmetic number, because the mean of its divisors is an integer number (3043064160).

Almost surely, 2^81978112097 is an apocalyptic number.

It is an amenable number.

81978112097 is a deficient number, since it is larger than the sum of its proper divisors (15399941023).

81978112097 is a wasteful number, since it uses less digits than its factorization.

81978112097 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5441.

The product of its (nonzero) digits is 508032, while the sum is 53.

The spelling of 81978112097 in words is "eighty-one billion, nine hundred seventy-eight million, one hundred twelve thousand, ninety-seven".