81436868140 has 12 divisors (see below), whose sum is σ = 171017423136. Its totient is φ = 32574747248.

The previous prime is 81436868129. The next prime is 81436868141. The reversal of 81436868140 is 4186863418.

It is not an unprimeable number, because it can be changed into a prime (81436868141) 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, 2035921684 + ... + 2035921723.

It is an arithmetic number, because the mean of its divisors is an integer number (14251451928).

Almost surely, 2^81436868140 is an apocalyptic number.

It is an amenable number.

81436868140 is an abundant number, since it is smaller than the sum of its proper divisors (89580554996).

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

81436868140 is a wasteful number, since it uses less digits than its factorization.

81436868140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4071843416 (or 4071843414 counting only the distinct ones).

The product of its (nonzero) digits is 884736, while the sum is 49.

The spelling of 81436868140 in words is "eighty-one billion, four hundred thirty-six million, eight hundred sixty-eight thousand, one hundred forty".