81430272 has 432 divisors, whose sum is σ = 321414912. Its totient is φ = 19906560.

The previous prime is 81430247. The next prime is 81430291. The reversal of 81430272 is 27203418.

It is a tau number, because it is divible by the number of its divisors (432).

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 4790008 + ... + 4790024.

It is an arithmetic number, because the mean of its divisors is an integer number (744016).

Almost surely, 2^81430272 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 81430272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160707456).

81430272 is an abundant number, since it is smaller than the sum of its proper divisors (239984640).

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

81430272 is a wasteful number, since it uses less digits than its factorization.

81430272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66 (or 40 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 81430272 is about 9023.8723395225. The cubic root of 81430272 is about 433.4396415048.

The spelling of 81430272 in words is "eighty-one million, four hundred thirty thousand, two hundred seventy-two".