81508788 has 24 divisors (see below), whose sum is σ = 211319360. Its totient is φ = 27169560.

The previous prime is 81508787. The next prime is 81508793. The reversal of 81508788 is 88780518.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81508787) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 377248 + ... + 377463.

Almost surely, 2^81508788 is an apocalyptic number.

It is an amenable number.

81508788 is an abundant number, since it is smaller than the sum of its proper divisors (129810572).

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

81508788 is a wasteful number, since it uses less digits than its factorization.

81508788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 754724 (or 754716 counting only the distinct ones).

The product of its (nonzero) digits is 143360, while the sum is 45.

The square root of 81508788 is about 9028.2217518180. The cubic root of 81508788 is about 433.5789059082.

The spelling of 81508788 in words is "eighty-one million, five hundred eight thousand, seven hundred eighty-eight".