81578404 has 6 divisors (see below), whose sum is σ = 142762214. Its totient is φ = 40789200.

The previous prime is 81578389. The next prime is 81578423. The reversal of 81578404 is 40487518.

It can be written as a sum of positive squares in only one way, i.e., 72590400 + 8988004 = 8520^2 + 2998^2 .

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 as a sum of consecutive naturals, namely, 10197297 + ... + 10197304.

Almost surely, 2^81578404 is an apocalyptic number.

It is an amenable number.

81578404 is a deficient number, since it is larger than the sum of its proper divisors (61183810).

81578404 is a wasteful number, since it uses less digits than its factorization.

81578404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20394605 (or 20394603 counting only the distinct ones).

The product of its (nonzero) digits is 35840, while the sum is 37.

The square root of 81578404 is about 9032.0763947168. The cubic root of 81578404 is about 433.7023095338.

It can be divided in two parts, 8157 and 8404, that added together give a palindrome (16561).

The spelling of 81578404 in words is "eighty-one million, five hundred seventy-eight thousand, four hundred four".