81442988 has 24 divisors (see below), whose sum is σ = 164629584. Its totient is φ = 34841600.

The previous prime is 81442979. The next prime is 81443009. The reversal of 81442988 is 88924418.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53693 + ... + 55188.

It is an arithmetic number, because the mean of its divisors is an integer number (6859566).

Almost surely, 2^81442988 is an apocalyptic number.

It is an amenable number.

81442988 is an abundant number, since it is smaller than the sum of its proper divisors (83186596).

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

81442988 is a wasteful number, since it uses less digits than its factorization.

81442988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108913 (or 108911 counting only the distinct ones).

The product of its digits is 147456, while the sum is 44.

The square root of 81442988 is about 9024.5768875887. The cubic root of 81442988 is about 433.4622020402.

The spelling of 81442988 in words is "eighty-one million, four hundred forty-two thousand, nine hundred eighty-eight".