81442209156 has 96 divisors (see below), whose sum is σ = 243326211072. Its totient is φ = 20582087040.

The previous prime is 81442209151. The next prime is 81442209181. The reversal of 81442209156 is 65190224418.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (81442209151) 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, 1156906 + ... + 1225281.

It is an arithmetic number, because the mean of its divisors is an integer number (2534648032).

Almost surely, 2^81442209156 is an apocalyptic number.

It is an amenable number.

81442209156 is an abundant number, since it is smaller than the sum of its proper divisors (161884001916).

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

81442209156 is a wasteful number, since it uses less digits than its factorization.

81442209156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2382249 (or 2382247 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 42.

The spelling of 81442209156 in words is "eighty-one billion, four hundred forty-two million, two hundred nine thousand, one hundred fifty-six".