81448636 has 12 divisors (see below), whose sum is σ = 142598512. Its totient is φ = 40706208.

The previous prime is 81448613. The next prime is 81448637. The reversal of 81448636 is 63684418.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81448637) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14161 + ... + 19063.

Almost surely, 2^81448636 is an apocalyptic number.

It is an amenable number.

81448636 is a deficient number, since it is larger than the sum of its proper divisors (61149876).

81448636 is a wasteful number, since it uses less digits than its factorization.

81448636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9060 (or 9058 counting only the distinct ones).

The product of its digits is 110592, while the sum is 40.

The square root of 81448636 is about 9024.8898054214. The cubic root of 81448636 is about 433.4722218835.

The spelling of 81448636 in words is "eighty-one million, four hundred forty-eight thousand, six hundred thirty-six".