81494040 has 128 divisors (see below), whose sum is σ = 265881600. Its totient is φ = 19906560.

The previous prime is 81494033. The next prime is 81494051. The reversal of 81494040 is 4049418.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 81493989 and 81494007.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 70104 + ... + 71256.

It is an arithmetic number, because the mean of its divisors is an integer number (2077200).

Almost surely, 2^81494040 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81494040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132940800).

81494040 is an abundant number, since it is smaller than the sum of its proper divisors (184387560).

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

81494040 is a wasteful number, since it uses less digits than its factorization.

81494040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1217 (or 1213 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 81494040 is about 9027.4049427286. The cubic root of 81494040 is about 433.5527540966.

The spelling of 81494040 in words is "eighty-one million, four hundred ninety-four thousand, forty".