81445625 has 20 divisors (see below), whose sum is σ = 102567168. Its totient is φ = 64650000.

The previous prime is 81445619. The next prime is 81445633. The reversal of 81445625 is 52654418.

It is not a de Polignac number, because 81445625 - 2⁶ = 81445561 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 93944 + ... + 94806.

Almost surely, 2^81445625 is an apocalyptic number.

It is an amenable number.

81445625 is a deficient number, since it is larger than the sum of its proper divisors (21121543).

81445625 is an equidigital number, since it uses as much as digits as its factorization.

81445625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1034 (or 1019 counting only the distinct ones).

The product of its digits is 38400, while the sum is 35.

The square root of 81445625 is about 9024.7229874385. The cubic root of 81445625 is about 433.4668802718.

The spelling of 81445625 in words is "eighty-one million, four hundred forty-five thousand, six hundred twenty-five".