81845120 has 64 divisors (see below), whose sum is σ = 223624800. Its totient is φ = 28059648.

The previous prime is 81845111. The next prime is 81845129. The reversal of 81845120 is 2154818.

It is an interprime number because it is at equal distance from previous prime (81845111) and next prime (81845129).

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81845129) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 4655 + ... + 13614.

Almost surely, 2^81845120 is an apocalyptic number.

81845120 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81845120 is an abundant number, since it is smaller than the sum of its proper divisors (141779680).

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

81845120 is a wasteful number, since it uses less digits than its factorization.

81845120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18295 (or 18283 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 29.

The square root of 81845120 is about 9046.8292788137. The cubic root of 81845120 is about 434.1744504572.

Adding to 81845120 its reverse (2154818), we get a palindrome (83999938).

The spelling of 81845120 in words is "eighty-one million, eight hundred forty-five thousand, one hundred twenty".