81956672 has 56 divisors (see below), whose sum is σ = 188976000. Its totient is φ = 34536960.

The previous prime is 81956627. The next prime is 81956683. The reversal of 81956672 is 27665918.

It is a tau number, because it is divible by the number of its divisors (56).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25829 + ... + 28827.

Almost surely, 2^81956672 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 81956672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94488000).

81956672 is an abundant number, since it is smaller than the sum of its proper divisors (107019328).

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

81956672 is a wasteful number, since it uses less digits than its factorization.

81956672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3079 (or 3069 counting only the distinct ones).

The product of its digits is 181440, while the sum is 44.

The square root of 81956672 is about 9052.9924334443. The cubic root of 81956672 is about 434.3716157078.

It can be divided in two parts, 81956 and 672, that added together give a palindrome (82628).

The spelling of 81956672 in words is "eighty-one million, nine hundred fifty-six thousand, six hundred seventy-two".