81641472 has 120 divisors (see below), whose sum is σ = 239068032. Its totient is φ = 24576000.

The previous prime is 81641419. The next prime is 81641489. The reversal of 81641472 is 27414618.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 540597 + ... + 540747.

Almost surely, 2^81641472 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81641472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119534016).

81641472 is an abundant number, since it is smaller than the sum of its proper divisors (157426560).

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

81641472 is a wasteful number, since it uses less digits than its factorization.

81641472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193 (or 167 counting only the distinct ones).

The product of its digits is 10752, while the sum is 33.

The square root of 81641472 is about 9035.5670547011. The cubic root of 81641472 is about 433.8140453616.

The spelling of 81641472 in words is "eighty-one million, six hundred forty-one thousand, four hundred seventy-two".