81520032 has 192 divisors, whose sum is σ = 261273600. Its totient is φ = 21934080.

The previous prime is 81520009. The next prime is 81520057. The reversal of 81520032 is 23002518.

It is a junction number, because it is equal to n+sod(n) for n = 81519990 and 81520008.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 340969 + ... + 341207.

It is an arithmetic number, because the mean of its divisors is an integer number (1360800).

Almost surely, 2^81520032 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 81520032, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130636800).

81520032 is an abundant number, since it is smaller than the sum of its proper divisors (179753568).

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

81520032 is a wasteful number, since it uses less digits than its factorization.

81520032 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299 (or 291 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 81520032 is about 9028.8444443351. The cubic root of 81520032 is about 433.5988421514.

The spelling of 81520032 in words is "eighty-one million, five hundred twenty thousand, thirty-two".