81051872 has 48 divisors (see below), whose sum is σ = 183254400. Its totient is φ = 34899840.

The previous prime is 81051871. The next prime is 81051877. The reversal of 81051872 is 27815018.

It is a happy number.

It is a super-5 number, since 5×81051872⁵ (a number of 41 digits) contains 55555 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81051871) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 629 + ... + 12747.

It is an arithmetic number, because the mean of its divisors is an integer number (3817800).

Almost surely, 2^81051872 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 81051872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91627200).

81051872 is an abundant number, since it is smaller than the sum of its proper divisors (102202528).

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

81051872 is a wasteful number, since it uses less digits than its factorization.

81051872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12159 (or 12151 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 81051872 is about 9002.8813165564. The cubic root of 81051872 is about 432.7672123337.

The spelling of 81051872 in words is "eighty-one million, fifty-one thousand, eight hundred seventy-two".