81527520 has 96 divisors (see below), whose sum is σ = 265144320. Its totient is φ = 21035520.

The previous prime is 81527513. The next prime is 81527549. The reversal of 81527520 is 2572518.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12141 + ... + 17619.

It is an arithmetic number, because the mean of its divisors is an integer number (2761920).

Almost surely, 2^81527520 is an apocalyptic number.

81527520 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81527520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132572160).

81527520 is an abundant number, since it is smaller than the sum of its proper divisors (183616800).

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

81527520 is a wasteful number, since it uses less digits than its factorization.

81527520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5528 (or 5520 counting only the distinct ones).

The product of its (nonzero) digits is 5600, while the sum is 30.

The square root of 81527520 is about 9029.2591058182. The cubic root of 81527520 is about 433.6121177788.

The spelling of 81527520 in words is "eighty-one million, five hundred twenty-seven thousand, five hundred twenty".