81270224 has 60 divisors (see below), whose sum is σ = 191175264. Its totient is φ = 33308352.

The previous prime is 81270187. The next prime is 81270229. The reversal of 81270224 is 42207218.

It is a Cunningham number, because it is equal to 9015²-1.

It is a junction number, because it is equal to n+sod(n) for n = 81270193 and 81270202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81270229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15779 + ... + 20285.

Almost surely, 2^81270224 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 81270224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95587632).

81270224 is an abundant number, since it is smaller than the sum of its proper divisors (109905040).

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

81270224 is a wasteful number, since it uses less digits than its factorization.

81270224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4552 (or 4539 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 81270224 is about 9014.9999445369. Note that the first 4 decimals coincide. The cubic root of 81270224 is about 433.1554857296.

The spelling of 81270224 in words is "eighty-one million, two hundred seventy thousand, two hundred twenty-four".