81754920 has 192 divisors, whose sum is σ = 297198720. Its totient is φ = 20093184.

The previous prime is 81754913. The next prime is 81754951. The reversal of 81754920 is 2945718.

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

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, 126037 + ... + 126683.

It is an arithmetic number, because the mean of its divisors is an integer number (1547910).

Almost surely, 2^81754920 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 81754920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148599360).

81754920 is an abundant number, since it is smaller than the sum of its proper divisors (215443800).

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

81754920 is a wasteful number, since it uses less digits than its factorization.

81754920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 686 (or 670 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 81754920 is about 9041.8427325408. The cubic root of 81754920 is about 434.0148932716.

The spelling of 81754920 in words is "eighty-one million, seven hundred fifty-four thousand, nine hundred twenty".