81227500 has 30 divisors (see below), whose sum is σ = 177633764. Its totient is φ = 32490000.

The previous prime is 81227459. The next prime is 81227501. The reversal of 81227500 is 572218.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is not an unprimeable number, because it can be changed into a prime (81227501) 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 9 ways as a sum of consecutive naturals, for example, 13746 + ... + 18745.

Almost surely, 2^81227500 is an apocalyptic number.

It is an amenable number.

81227500 is an abundant number, since it is smaller than the sum of its proper divisors (96406264).

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

81227500 is a wasteful number, since it uses less digits than its factorization.

81227500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32515 (or 32498 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 81227500 is about 9012.6300268013. The cubic root of 81227500 is about 433.0795687130.

Adding to 81227500 its reverse (572218), we get a palindrome (81799718).

The spelling of 81227500 in words is "eighty-one million, two hundred twenty-seven thousand, five hundred".