81356340 has 96 divisors (see below), whose sum is σ = 252040320. Its totient is φ = 19478016.

The previous prime is 81356323. The next prime is 81356357. The reversal of 81356340 is 4365318.

It is an interprime number because it is at equal distance from previous prime (81356323) and next prime (81356357).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 81356298 and 81356307.

It is a congruent number.

It is an unprimeable number.

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, 27451 + ... + 30269.

It is an arithmetic number, because the mean of its divisors is an integer number (2625420).

Almost surely, 2^81356340 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 81356340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126020160).

81356340 is an abundant number, since it is smaller than the sum of its proper divisors (170683980).

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

81356340 is a wasteful number, since it uses less digits than its factorization.

81356340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2881 (or 2879 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 81356340 is about 9019.7749417599. The cubic root of 81356340 is about 433.3084259188.

The spelling of 81356340 in words is "eighty-one million, three hundred fifty-six thousand, three hundred forty".