81180144 has 50 divisors (see below), whose sum is σ = 234962640. Its totient is φ = 27059616.

The previous prime is 81180137. The next prime is 81180149. The reversal of 81180144 is 44108118.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81180149) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 30024 + ... + 32615.

Almost surely, 2^81180144 is an apocalyptic number.

It is an amenable number.

81180144 is an abundant number, since it is smaller than the sum of its proper divisors (153782496).

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

81180144 is a wasteful number, since it uses less digits than its factorization.

81180144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62659 (or 62644 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 27.

The square root of 81180144 is about 9010.0024417311. The cubic root of 81180144 is about 432.9953899027.

The spelling of 81180144 in words is "eighty-one million, one hundred eighty thousand, one hundred forty-four".