81084870 has 96 divisors (see below), whose sum is σ = 223067520. Its totient is φ = 20401920.

The previous prime is 81084851. The next prime is 81084901. The reversal of 81084870 is 7848018.

It is a super-2 number, since 2×81084870² = 13149512285833800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 122340 + ... + 123000.

It is an arithmetic number, because the mean of its divisors is an integer number (2323620).

Almost surely, 2^81084870 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81084870, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111533760).

81084870 is an abundant number, since it is smaller than the sum of its proper divisors (141982650).

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

81084870 is a wasteful number, since it uses less digits than its factorization.

81084870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 750 (or 747 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 81084870 is about 9004.7137655786. The cubic root of 81084870 is about 432.8259340493.

The spelling of 81084870 in words is "eighty-one million, eighty-four thousand, eight hundred seventy".