81228525 has 108 divisors (see below), whose sum is σ = 168444576. Its totient is φ = 34372800.

The previous prime is 81228523. The next prime is 81228541. The reversal of 81228525 is 52582218.

It is not a de Polignac number, because 81228525 - 2¹ = 81228523 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81228523) 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 107 ways as a sum of consecutive naturals, for example, 2620260 + ... + 2620290.

It is an arithmetic number, because the mean of its divisors is an integer number (1559672).

Almost surely, 2^81228525 is an apocalyptic number.

It is an amenable number.

81228525 is an abundant number, since it is smaller than the sum of its proper divisors (87216051).

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

81228525 is a wasteful number, since it uses less digits than its factorization.

81228525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112 (or 69 counting only the distinct ones).

The product of its digits is 12800, while the sum is 33.

The square root of 81228525 is about 9012.6868912661. The cubic root of 81228525 is about 433.0813903649.

The spelling of 81228525 in words is "eighty-one million, two hundred twenty-eight thousand, five hundred twenty-five".