81436748440 has 64 divisors (see below), whose sum is σ = 185206500000. Its totient is φ = 32224358400.

The previous prime is 81436748417. The next prime is 81436748441. The reversal of 81436748440 is 4484763418.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81436748441) 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, 5037891 + ... + 5054029.

Almost surely, 2^81436748440 is an apocalyptic number.

It is an amenable number.

81436748440 is an abundant number, since it is smaller than the sum of its proper divisors (103769751560).

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

81436748440 is a wasteful number, since it uses less digits than its factorization.

81436748440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17500 (or 17496 counting only the distinct ones).

The product of its (nonzero) digits is 2064384, while the sum is 49.

The spelling of 81436748440 in words is "eighty-one billion, four hundred thirty-six million, seven hundred forty-eight thousand, four hundred forty".