81761472 has 168 divisors, whose sum is σ = 257952240. Its totient is φ = 24606720.

The previous prime is 81761467. The next prime is 81761479. The reversal of 81761472 is 27416718.

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 (81761479) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 456679 + ... + 456857.

It is an arithmetic number, because the mean of its divisors is an integer number (1535430).

Almost surely, 2^81761472 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 81761472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128976120).

81761472 is an abundant number, since it is smaller than the sum of its proper divisors (176190768).

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

81761472 is a wasteful number, since it uses less digits than its factorization.

81761472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271 (or 258 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 81761472 is about 9042.2050408072. The cubic root of 81761472 is about 434.0264872308.

The spelling of 81761472 in words is "eighty-one million, seven hundred sixty-one thousand, four hundred seventy-two".