81544684452 has 144 divisors (see below), whose sum is σ = 246729240576. Its totient is φ = 20497118400.

The previous prime is 81544684447. The next prime is 81544684457. The reversal of 81544684452 is 25448644518.

It is an interprime number because it is at equal distance from previous prime (81544684447) and next prime (81544684457).

It is a junction number, because it is equal to n+sod(n) for n = 81544684395 and 81544684404.

It is not an unprimeable number, because it can be changed into a prime (81544684457) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 185683 + ... + 444485.

It is an arithmetic number, because the mean of its divisors is an integer number (1713397504).

Almost surely, 2^81544684452 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 81544684452, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123364620288).

81544684452 is an abundant number, since it is smaller than the sum of its proper divisors (165184556124).

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

81544684452 is a wasteful number, since it uses less digits than its factorization.

81544684452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 258870 (or 258857 counting only the distinct ones).

The product of its digits is 4915200, while the sum is 51.

The spelling of 81544684452 in words is "eighty-one billion, five hundred forty-four million, six hundred eighty-four thousand, four hundred fifty-two".