81183960 has 384 divisors, whose sum is σ = 330220800. Its totient is φ = 17003520.

The previous prime is 81183953. The next prime is 81183961. The reversal of 81183960 is 6938118.

It is a super-2 number, since 2×81183960² = 13181670722563200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81183961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 978079 + ... + 978161.

It is an arithmetic number, because the mean of its divisors is an integer number (859950).

Almost surely, 2^81183960 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 81183960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165110400).

81183960 is an abundant number, since it is smaller than the sum of its proper divisors (249036840).

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

81183960 is a wasteful number, since it uses less digits than its factorization.

81183960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143 (or 136 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 81183960 is about 9010.2142038910. The cubic root of 81183960 is about 433.0021743389.

It can be divided in two parts, 81 and 183960, that added together give a square (184041 = 429²).

The spelling of 81183960 in words is "eighty-one million, one hundred eighty-three thousand, nine hundred sixty".