81831225 has 48 divisors (see below), whose sum is σ = 157827200. Its totient is φ = 37396800.

The previous prime is 81831221. The next prime is 81831229. The reversal of 81831225 is 52213818.

It is an interprime number because it is at equal distance from previous prime (81831221) and next prime (81831229).

It is not a de Polignac number, because 81831225 - 2² = 81831221 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81831192 and 81831201.

It is not an unprimeable number, because it can be changed into a prime (81831221) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 24135 + ... + 27315.

Almost surely, 2^81831225 is an apocalyptic number.

It is an amenable number.

81831225 is a deficient number, since it is larger than the sum of its proper divisors (75995975).

81831225 is a wasteful number, since it uses less digits than its factorization.

81831225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3215 (or 3196 counting only the distinct ones).

The product of its digits is 3840, while the sum is 30.

The square root of 81831225 is about 9046.0612976035. The cubic root of 81831225 is about 434.1498788622.

The spelling of 81831225 in words is "eighty-one million, eight hundred thirty-one thousand, two hundred twenty-five".