81723012 has 96 divisors (see below), whose sum is σ = 232888320. Its totient is φ = 21772800.

The previous prime is 81722969. The next prime is 81723041. The reversal of 81723012 is 21032718.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 215439 + ... + 215817.

It is an arithmetic number, because the mean of its divisors is an integer number (2425920).

Almost surely, 2^81723012 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 81723012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116444160).

81723012 is an abundant number, since it is smaller than the sum of its proper divisors (151165308).

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

81723012 is a wasteful number, since it uses less digits than its factorization.

81723012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 561 (or 559 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 81723012 is about 9040.0780970078. The cubic root of 81723012 is about 433.9584222594.

The spelling of 81723012 in words is "eighty-one million, seven hundred twenty-three thousand, twelve".