81291404 has 12 divisors (see below), whose sum is σ = 142353624. Its totient is φ = 40618944.

The previous prime is 81291403. The next prime is 81291449. The reversal of 81291404 is 40419218.

It is not an unprimeable number, because it can be changed into a prime (81291401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1172 + ... + 12804.

It is an arithmetic number, because the mean of its divisors is an integer number (11862802).

Almost surely, 2^81291404 is an apocalyptic number.

It is an amenable number.

81291404 is a deficient number, since it is larger than the sum of its proper divisors (61062220).

81291404 is a wasteful number, since it uses less digits than its factorization.

81291404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13384 (or 13382 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 81291404 is about 9016.1745768369. The cubic root of 81291404 is about 433.1931109748.

The spelling of 81291404 in words is "eighty-one million, two hundred ninety-one thousand, four hundred four".