81504774 has 48 divisors (see below), whose sum is σ = 192628800. Its totient is φ = 24755328.

The previous prime is 81504767. The next prime is 81504781. The reversal of 81504774 is 47740518.

81504774 is a `hidden beast` number, since 81 + 504 + 7 + 74 = 666.

It is an interprime number because it is at equal distance from previous prime (81504767) and next prime (81504781).

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 23 ways as a sum of consecutive naturals, for example, 16282 + ... + 20690.

It is an arithmetic number, because the mean of its divisors is an integer number (4013100).

Almost surely, 2^81504774 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81504774, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96314400).

81504774 is an abundant number, since it is smaller than the sum of its proper divisors (111124026).

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

81504774 is a wasteful number, since it uses less digits than its factorization.

81504774 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4509 (or 4506 counting only the distinct ones).

The product of its (nonzero) digits is 31360, while the sum is 36.

The square root of 81504774 is about 9027.9994461675. Note that the first 3 decimals coincide. The cubic root of 81504774 is about 433.5717884168.

The spelling of 81504774 in words is "eighty-one million, five hundred four thousand, seven hundred seventy-four".