81533025 has 36 divisors (see below), whose sum is σ = 166900032. Its totient is φ = 37271520.

The previous prime is 81533017. The next prime is 81533029. The reversal of 81533025 is 52033518.

It is not a de Polignac number, because 81533025 - 2³ = 81533017 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81533025.

It is not an unprimeable number, because it can be changed into a prime (81533029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 24309 + ... + 27458.

It is an arithmetic number, because the mean of its divisors is an integer number (4636112).

Almost surely, 2^81533025 is an apocalyptic number.

It is an amenable number.

81533025 is an abundant number, since it is smaller than the sum of its proper divisors (85367007).

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

81533025 is a wasteful number, since it uses less digits than its factorization.

81533025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51790 (or 51782 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 81533025 is about 9029.5639429598. The cubic root of 81533025 is about 433.6218771868.

The spelling of 81533025 in words is "eighty-one million, five hundred thirty-three thousand, twenty-five".