81144012 has 12 divisors (see below), whose sum is σ = 189336056. Its totient is φ = 27048000.

The previous prime is 81143999. The next prime is 81144013. The reversal of 81144012 is 21044118.

It is a happy number.

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

It is a super-2 number, since 2×81144012² = 13168701366912288, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81144012.

It is not an unprimeable number, because it can be changed into a prime (81144013) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3380989 + ... + 3381012.

Almost surely, 2^81144012 is an apocalyptic number.

It is an amenable number.

81144012 is an abundant number, since it is smaller than the sum of its proper divisors (108192044).

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

81144012 is a wasteful number, since it uses less digits than its factorization.

81144012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6762008 (or 6762006 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 21.

The square root of 81144012 is about 9007.9971136763. The cubic root of 81144012 is about 432.9311405664.

The spelling of 81144012 in words is "eighty-one million, one hundred forty-four thousand, twelve".