81208404 has 36 divisors (see below), whose sum is σ = 206650080. Its totient is φ = 26888400.

The previous prime is 81208403. The next prime is 81208409. The reversal of 81208404 is 40480218.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81208403) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2034 + ... + 12905.

It is an arithmetic number, because the mean of its divisors is an integer number (5740280).

Almost surely, 2^81208404 is an apocalyptic number.

It is an amenable number.

81208404 is an abundant number, since it is smaller than the sum of its proper divisors (125441676).

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

81208404 is a wasteful number, since it uses less digits than its factorization.

81208404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15100 (or 15095 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 81208404 is about 9011.5705623382. The cubic root of 81208404 is about 433.0456280910.

The spelling of 81208404 in words is "eighty-one million, two hundred eight thousand, four hundred four".