81894072 has 64 divisors (see below), whose sum is σ = 221760000. Its totient is φ = 25052544.

The previous prime is 81894041. The next prime is 81894073. The reversal of 81894072 is 27049818.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 81894072.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81894073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61429 + ... + 62747.

It is an arithmetic number, because the mean of its divisors is an integer number (3465000).

Almost surely, 2^81894072 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 81894072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110880000).

81894072 is an abundant number, since it is smaller than the sum of its proper divisors (139865928).

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

81894072 is a wasteful number, since it uses less digits than its factorization.

81894072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1540 (or 1536 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 39.

The square root of 81894072 is about 9049.5343526615. The cubic root of 81894072 is about 434.2609938854.

The spelling of 81894072 in words is "eighty-one million, eight hundred ninety-four thousand, seventy-two".