81616160 has 24 divisors (see below), whose sum is σ = 192818556. Its totient is φ = 32646400.

The previous prime is 81616159. The next prime is 81616163. The reversal of 81616160 is 6161618.

It can be written as a sum of positive squares in 2 ways, for example, as 73753744 + 7862416 = 8588^2 + 2804^2 .

It is a super-2 number, since 2×81616160² = 13322395146291200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81616163) 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 3 ways as a sum of consecutive naturals, for example, 254891 + ... + 255210.

Almost surely, 2^81616160 is an apocalyptic number.

81616160 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81616160 is an abundant number, since it is smaller than the sum of its proper divisors (111202396).

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

81616160 is a wasteful number, since it uses less digits than its factorization.

81616160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 510116 (or 510108 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 81616160 is about 9034.1662592627. The cubic root of 81616160 is about 433.7692077080.

Adding to 81616160 its reverse (6161618), we get a palindrome (87777778).

The spelling of 81616160 in words is "eighty-one million, six hundred sixteen thousand, one hundred sixty".