81508380 has 48 divisors (see below), whose sum is σ = 228631200. Its totient is φ = 21696768.

The previous prime is 81508379. The next prime is 81508403. The reversal of 81508380 is 8380518.

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, 51846 + ... + 53394.

It is an arithmetic number, because the mean of its divisors is an integer number (4763150).

Almost surely, 2^81508380 is an apocalyptic number.

It is an amenable number.

81508380 is an abundant number, since it is smaller than the sum of its proper divisors (147122820).

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

81508380 is a wasteful number, since it uses less digits than its factorization.

81508380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2438 (or 2436 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 33.

The square root of 81508380 is about 9028.1991559779. The cubic root of 81508380 is about 433.5781824668.

Adding to 81508380 its reverse (8380518), we get a palindrome (89888898).

The spelling of 81508380 in words is "eighty-one million, five hundred eight thousand, three hundred eighty".