81000144 has 30 divisors (see below), whose sum is σ = 226688306. Its totient is φ = 27000000.

The previous prime is 81000113. The next prime is 81000149. The reversal of 81000144 is 44100018.

It can be written as a sum of positive squares in only one way, i.e., 81000000 + 144 = 9000^2 + 12^2 .

It is a super-2 number, since 2×81000144² = 13122046656041472, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81000149) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 281107 + ... + 281394.

Almost surely, 2^81000144 is an apocalyptic number.

It is an amenable number.

81000144 is an abundant number, since it is smaller than the sum of its proper divisors (145688162).

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

81000144 is a wasteful number, since it uses less digits than its factorization.

81000144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 562515 (or 562506 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 81000144 is about 9000.0079999964. The cubic root of 81000144 is about 432.6751274920.

It can be divided in two parts, 8100014 and 4, that added together give a palindrome (8100018).

The spelling of 81000144 in words is "eighty-one million, one hundred forty-four", and thus it is an aban number.