81609360 has 160 divisors (see below), whose sum is σ = 298647552. Its totient is φ = 18040320.

The previous prime is 81609337. The next prime is 81609371. The reversal of 81609360 is 6390618.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51297 + ... + 52863.

Almost surely, 2^81609360 is an apocalyptic number.

81609360 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81609360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149323776).

81609360 is an abundant number, since it is smaller than the sum of its proper divisors (217038192).

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

81609360 is a wasteful number, since it uses less digits than its factorization.

81609360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1621 (or 1615 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 81609360 is about 9033.7899023610. The cubic root of 81609360 is about 433.7571606145.

Adding to 81609360 its reverse (6390618), we get a palindrome (87999978).

The spelling of 81609360 in words is "eighty-one million, six hundred nine thousand, three hundred sixty".