81265320 has 96 divisors (see below), whose sum is σ = 271294920. Its totient is φ = 21081600.

The previous prime is 81265267. The next prime is 81265333. The reversal of 81265320 is 2356218.

81265320 is a `hidden beast` number, since 8 + 1 + 2 + 653 + 2 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 78960996 + 2304324 = 8886^2 + 1518^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10270 + ... + 16370.

Almost surely, 2^81265320 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 81265320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135647460).

81265320 is an abundant number, since it is smaller than the sum of its proper divisors (190029600).

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

81265320 is a wasteful number, since it uses less digits than its factorization.

81265320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6155 (or 6148 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 81265320 is about 9014.7279493061. The cubic root of 81265320 is about 433.1467730789.

The spelling of 81265320 in words is "eighty-one million, two hundred sixty-five thousand, three hundred twenty".