81442512 has 180 divisors, whose sum is σ = 257339680. Its totient is φ = 23970816.

The previous prime is 81442477. The next prime is 81442547. The reversal of 81442512 is 21524418.

81442512 is a `hidden beast` number, since 8 + 144 + 2 + 512 = 666.

It is an interprime number because it is at equal distance from previous prime (81442477) and next prime (81442547).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 790653 + ... + 790755.

Almost surely, 2^81442512 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 81442512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128669840).

81442512 is an abundant number, since it is smaller than the sum of its proper divisors (175897168).

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

81442512 is a wasteful number, since it uses less digits than its factorization.

81442512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170 (or 144 counting only the distinct ones).

The product of its digits is 2560, while the sum is 27.

The square root of 81442512 is about 9024.5505151226. The cubic root of 81442512 is about 433.4613575705.

The spelling of 81442512 in words is "eighty-one million, four hundred forty-two thousand, five hundred twelve".