81210912 has 48 divisors (see below), whose sum is σ = 214889472. Its totient is φ = 26853120.

The previous prime is 81210911. The next prime is 81210923. The reversal of 81210912 is 21901218.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (81210911) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8862 + ... + 15522.

It is an arithmetic number, because the mean of its divisors is an integer number (4476864).

Almost surely, 2^81210912 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 81210912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107444736).

81210912 is an abundant number, since it is smaller than the sum of its proper divisors (133678560).

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

81210912 is a wasteful number, since it uses less digits than its factorization.

81210912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6801 (or 6793 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 24.

The square root of 81210912 is about 9011.7097156977. The cubic root of 81210912 is about 433.0500860338.

The spelling of 81210912 in words is "eighty-one million, two hundred ten thousand, nine hundred twelve".