81438492 has 36 divisors (see below), whose sum is σ = 198659720. Its totient is φ = 25963872.

The previous prime is 81438463. The next prime is 81438509. The reversal of 81438492 is 29483418.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 81438492.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 67 + ... + 12762.

Almost surely, 2^81438492 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 81438492, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99329860).

81438492 is an abundant number, since it is smaller than the sum of its proper divisors (117221228).

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

81438492 is a wasteful number, since it uses less digits than its factorization.

81438492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12882 (or 12857 counting only the distinct ones).

The product of its digits is 55296, while the sum is 39.

The square root of 81438492 is about 9024.3277866000. The cubic root of 81438492 is about 433.4542255732.

The spelling of 81438492 in words is "eighty-one million, four hundred thirty-eight thousand, four hundred ninety-two".