81529344 has 120 divisors (see below), whose sum is σ = 253585332. Its totient is φ = 25067520.

The previous prime is 81529337. The next prime is 81529351. The reversal of 81529344 is 44392518.

It is an interprime number because it is at equal distance from previous prime (81529337) and next prime (81529351).

It can be written as a sum of positive squares in 2 ways, for example, as 70560000 + 10969344 = 8400^2 + 3312^2 .

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 = 81529299 and 81529308.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 59224 + ... + 60584.

Almost surely, 2^81529344 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 81529344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126792666).

81529344 is an abundant number, since it is smaller than the sum of its proper divisors (172055988).

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

81529344 is a wasteful number, since it uses less digits than its factorization.

81529344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1398 (or 1379 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 81529344 is about 9029.3601102182. The cubic root of 81529344 is about 433.6153514624.

The spelling of 81529344 in words is "eighty-one million, five hundred twenty-nine thousand, three hundred forty-four".