81904870 has 8 divisors (see below), whose sum is σ = 147428784. Its totient is φ = 32761944.

The previous prime is 81904843. The next prime is 81904891. The reversal of 81904870 is 7840918.

It is a sphenic number, since it is the product of 3 distinct primes.

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 3 ways as a sum of consecutive naturals, for example, 4095234 + ... + 4095253.

It is an arithmetic number, because the mean of its divisors is an integer number (18428598).

Almost surely, 2^81904870 is an apocalyptic number.

81904870 is a deficient number, since it is larger than the sum of its proper divisors (65523914).

81904870 is a wasteful number, since it uses less digits than its factorization.

81904870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8190494.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 81904870 is about 9050.1309382793. The cubic root of 81904870 is about 434.2800792885.

The spelling of 81904870 in words is "eighty-one million, nine hundred four thousand, eight hundred seventy".