81387000 has 96 divisors (see below), whose sum is σ = 275118480. Its totient is φ = 21700800.

The previous prime is 81386999. The next prime is 81387049. The reversal of 81387000 is 78318.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4479 + ... + 13521.

Almost surely, 2^81387000 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 81387000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137559240).

81387000 is an abundant number, since it is smaller than the sum of its proper divisors (193731480).

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

81387000 is a wasteful number, since it uses less digits than its factorization.

81387000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9070 (or 9053 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 81387000 is about 9021.4743806099. The cubic root of 81387000 is about 433.3628513752.

The spelling of 81387000 in words is "eighty-one million, three hundred eighty-seven thousand".