81867240 has 512 divisors, whose sum is σ = 362880000. Its totient is φ = 16257024.

The previous prime is 81867173. The next prime is 81867259. The reversal of 81867240 is 4276818.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81867195 and 81867204.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 4815712 + ... + 4815728.

It is an arithmetic number, because the mean of its divisors is an integer number (708750).

Almost surely, 2^81867240 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 81867240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (181440000).

81867240 is an abundant number, since it is smaller than the sum of its proper divisors (281012760).

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

81867240 is a wasteful number, since it uses less digits than its factorization.

81867240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 81867240 is about 9048.0517239901. The cubic root of 81867240 is about 434.2135612141.

The spelling of 81867240 in words is "eighty-one million, eight hundred sixty-seven thousand, two hundred forty".