81262500 has 144 divisors (see below), whose sum is σ = 259858368. Its totient is φ = 19600000.

The previous prime is 81262477. The next prime is 81262507. The reversal of 81262500 is 526218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81262507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 412402 + ... + 412598.

It is an arithmetic number, because the mean of its divisors is an integer number (1804572).

Almost surely, 2^81262500 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81262500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129929184).

81262500 is an abundant number, since it is smaller than the sum of its proper divisors (178595868).

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

81262500 is a wasteful number, since it uses less digits than its factorization.

81262500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 218 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 81262500 is about 9014.5715372390. The cubic root of 81262500 is about 433.1417627906.

Adding to 81262500 its reverse (526218), we get a palindrome (81788718).

The spelling of 81262500 in words is "eighty-one million, two hundred sixty-two thousand, five hundred".