81810448 has 20 divisors (see below), whose sum is σ = 165400128. Its totient is φ = 39126560.

The previous prime is 81810439. The next prime is 81810451. The reversal of 81810448 is 84401818.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110788 + ... + 111523.

Almost surely, 2^81810448 is an apocalyptic number.

It is an amenable number.

81810448 is an abundant number, since it is smaller than the sum of its proper divisors (83589680).

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

81810448 is a wasteful number, since it uses less digits than its factorization.

81810448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222342 (or 222336 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 34.

The square root of 81810448 is about 9044.9128243450. The cubic root of 81810448 is about 434.1131321087.

The spelling of 81810448 in words is "eighty-one million, eight hundred ten thousand, four hundred forty-eight".