81053720 has 64 divisors (see below), whose sum is σ = 203847840. Its totient is φ = 28748800.

The previous prime is 81053699. The next prime is 81053723. The reversal of 81053720 is 2735018.

It is a self number, because there is not a number n which added to its sum of digits gives 81053720.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81053723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15794 + ... + 20286.

Almost surely, 2^81053720 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 81053720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101923920).

81053720 is an abundant number, since it is smaller than the sum of its proper divisors (122794120).

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

81053720 is a wasteful number, since it uses less digits than its factorization.

81053720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4556 (or 4552 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 81053720 is about 9002.9839497802. The cubic root of 81053720 is about 432.7705013703.

Adding to 81053720 its reverse (2735018), we get a palindrome (83788738).

The spelling of 81053720 in words is "eighty-one million, fifty-three thousand, seven hundred twenty".