81436225 has 48 divisors (see below), whose sum is σ = 114992640. Its totient is φ = 56793600.

The previous prime is 81436211. The next prime is 81436237. The reversal of 81436225 is 52263418.

It is not a de Polignac number, because 81436225 - 2⁵ = 81436193 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 594357 + ... + 594493.

It is an arithmetic number, because the mean of its divisors is an integer number (2395680).

Almost surely, 2^81436225 is an apocalyptic number.

It is an amenable number.

81436225 is a deficient number, since it is larger than the sum of its proper divisors (33556415).

81436225 is a wasteful number, since it uses less digits than its factorization.

81436225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250 (or 245 counting only the distinct ones).

The product of its digits is 11520, while the sum is 31.

The square root of 81436225 is about 9024.2021808025. The cubic root of 81436225 is about 433.4502035200.

The spelling of 81436225 in words is "eighty-one million, four hundred thirty-six thousand, two hundred twenty-five".