81436672 has 28 divisors (see below), whose sum is σ = 162879786. Its totient is φ = 40714240.

The previous prime is 81436661. The next prime is 81436723. The reversal of 81436672 is 27663418.

It can be written as a sum of positive squares in only one way, i.e., 81432576 + 4096 = 9024^2 + 64^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3222 + ... + 13162.

Almost surely, 2^81436672 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 81436672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81439893).

81436672 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81436672 is an frugal number, since it uses more digits than its factorization.

81436672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9967 (or 9943 counting only the distinct ones).

The product of its digits is 48384, while the sum is 37.

The square root of 81436672 is about 9024.2269475008. The cubic root of 81436672 is about 433.4509965818.

The spelling of 81436672 in words is "eighty-one million, four hundred thirty-six thousand, six hundred seventy-two".