81508428 has 36 divisors (see below), whose sum is σ = 206955840. Its totient is φ = 27048096.

The previous prime is 81508417. The next prime is 81508429. The reversal of 81508428 is 82480518.

It is a tau number, because it is divible by the number of its divisors (36).

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 = 81508392 and 81508401.

It is not an unprimeable number, because it can be changed into a prime (81508429) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3301 + ... + 13187.

Almost surely, 2^81508428 is an apocalyptic number.

It is an amenable number.

81508428 is an abundant number, since it is smaller than the sum of its proper divisors (125447412).

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

81508428 is a wasteful number, since it uses less digits than its factorization.

81508428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10126 (or 10121 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 36.

The square root of 81508428 is about 9028.2018143150. The cubic root of 81508428 is about 433.5782675777.

The spelling of 81508428 in words is "eighty-one million, five hundred eight thousand, four hundred twenty-eight".