81145872 has 60 divisors (see below), whose sum is σ = 229342464. Its totient is φ = 26781120.

The previous prime is 81145871. The next prime is 81145873. The reversal of 81145872 is 27854118.

It is an interprime number because it is at equal distance from previous prime (81145871) and next prime (81145873).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (81145871) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12097 + ... + 17567.

Almost surely, 2^81145872 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 81145872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114671232).

81145872 is an abundant number, since it is smaller than the sum of its proper divisors (148196592).

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

81145872 is a wasteful number, since it uses less digits than its factorization.

81145872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5588 (or 5579 counting only the distinct ones).

The product of its digits is 17920, while the sum is 36.

The square root of 81145872 is about 9008.1003546808. The cubic root of 81145872 is about 432.9344484538.

The spelling of 81145872 in words is "eighty-one million, one hundred forty-five thousand, eight hundred seventy-two".