81756164 has 48 divisors (see below), whose sum is σ = 173107200. Its totient is φ = 33003936.

The previous prime is 81756149. The next prime is 81756187. The reversal of 81756164 is 46165718.

It is a super-3 number, since 3×81756164³ (a number of 25 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 126827 + ... + 127469.

It is an arithmetic number, because the mean of its divisors is an integer number (3606400).

Almost surely, 2^81756164 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 81756164, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86553600).

81756164 is an abundant number, since it is smaller than the sum of its proper divisors (91351036).

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

81756164 is a wasteful number, since it uses less digits than its factorization.

81756164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 912 (or 910 counting only the distinct ones).

The product of its digits is 40320, while the sum is 38.

The square root of 81756164 is about 9041.9115235662. The cubic root of 81756164 is about 434.0170946143.

The spelling of 81756164 in words is "eighty-one million, seven hundred fifty-six thousand, one hundred sixty-four".