81596340 has 144 divisors (see below), whose sum is σ = 292131840. Its totient is φ = 18040320.

The previous prime is 81596297. The next prime is 81596353. The reversal of 81596340 is 4369518.

81596340 is a `hidden beast` number, since 8 + 15 + 9 + 634 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81596295 and 81596304.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 38016 + ... + 40104.

Almost surely, 2^81596340 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 81596340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (146065920).

81596340 is an abundant number, since it is smaller than the sum of its proper divisors (210535500).

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

81596340 is a wasteful number, since it uses less digits than its factorization.

81596340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2142 (or 2137 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 81596340 is about 9033.0692458322. The cubic root of 81596340 is about 433.7340921062.

It can be divided in two parts, 815963 and 40, that added together give a triangular number (816003 = T₁₂₇₇).

The spelling of 81596340 in words is "eighty-one million, five hundred ninety-six thousand, three hundred forty".