81055620 has 96 divisors (see below), whose sum is σ = 253478400. Its totient is φ = 21503232.

The previous prime is 81055613. The next prime is 81055627. The reversal of 81055620 is 2655018.

It is an interprime number because it is at equal distance from previous prime (81055613) and next prime (81055627).

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

It is not an unprimeable number, because it can be changed into a prime (81055627) 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 31 ways as a sum of consecutive naturals, for example, 197976 + ... + 198384.

It is an arithmetic number, because the mean of its divisors is an integer number (2640400).

Almost surely, 2^81055620 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 81055620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126739200).

81055620 is an abundant number, since it is smaller than the sum of its proper divisors (172422780).

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

81055620 is a wasteful number, since it uses less digits than its factorization.

81055620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 794 (or 786 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 81055620 is about 9003.0894697320. The cubic root of 81055620 is about 432.7738829035.

The spelling of 81055620 in words is "eighty-one million, fifty-five thousand, six hundred twenty".