81508120 has 32 divisors (see below), whose sum is σ = 184575600. Its totient is φ = 32393088.

The previous prime is 81508103. The next prime is 81508121. The reversal of 81508120 is 2180518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81508121) 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, 210 + ... + 12769.

Almost surely, 2^81508120 is an apocalyptic number.

It is an amenable number.

81508120 is an abundant number, since it is smaller than the sum of its proper divisors (103067480).

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

81508120 is a wasteful number, since it uses less digits than its factorization.

81508120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13147 (or 13143 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 25.

The square root of 81508120 is about 9028.1847566385. The cubic root of 81508120 is about 433.5777214490.

Adding to 81508120 its reverse (2180518), we get a palindrome (83688638).

The spelling of 81508120 in words is "eighty-one million, five hundred eight thousand, one hundred twenty".