81319452 has 12 divisors (see below), whose sum is σ = 189745416. Its totient is φ = 27106480.

The previous prime is 81319423. The next prime is 81319453. The reversal of 81319452 is 25491318.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×81319452² = 13225706547160608, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81319453) 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 3 ways as a sum of consecutive naturals, for example, 3388299 + ... + 3388322.

It is an arithmetic number, because the mean of its divisors is an integer number (15812118).

Almost surely, 2^81319452 is an apocalyptic number.

It is an amenable number.

81319452 is an abundant number, since it is smaller than the sum of its proper divisors (108425964).

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

81319452 is a wasteful number, since it uses less digits than its factorization.

81319452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6776628 (or 6776626 counting only the distinct ones).

The product of its digits is 8640, while the sum is 33.

The square root of 81319452 is about 9017.7298695403. The cubic root of 81319452 is about 433.2429268334.

The spelling of 81319452 in words is "eighty-one million, three hundred nineteen thousand, four hundred fifty-two".