81438612 has 48 divisors (see below), whose sum is σ = 202944000. Its totient is φ = 25361280.

The previous prime is 81438611. The next prime is 81438613. The reversal of 81438612 is 21683418.

It is an interprime number because it is at equal distance from previous prime (81438611) and next prime (81438613).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81438611) 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, 7014 + ... + 14562.

It is an arithmetic number, because the mean of its divisors is an integer number (4228000).

Almost surely, 2^81438612 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 81438612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101472000).

81438612 is an abundant number, since it is smaller than the sum of its proper divisors (121505388).

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

81438612 is a wasteful number, since it uses less digits than its factorization.

81438612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7616 (or 7614 counting only the distinct ones).

The product of its digits is 9216, while the sum is 33.

The square root of 81438612 is about 9024.3344352922. The cubic root of 81438612 is about 433.4544384720.

The spelling of 81438612 in words is "eighty-one million, four hundred thirty-eight thousand, six hundred twelve".