81904023 has 6 divisors (see below), whose sum is σ = 118305824. Its totient is φ = 54602676.

The previous prime is 81904013. The next prime is 81904057. The reversal of 81904023 is 32040918.

It is not a de Polignac number, because 81904023 - 2⁴ = 81904007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81904013) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 4550215 + ... + 4550232.

Almost surely, 2^81904023 is an apocalyptic number.

81904023 is a deficient number, since it is larger than the sum of its proper divisors (36401801).

81904023 is a wasteful number, since it uses less digits than its factorization.

81904023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9100453 (or 9100450 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 81904023 is about 9050.0841432552. The cubic root of 81904023 is about 434.2785822815.

The spelling of 81904023 in words is "eighty-one million, nine hundred four thousand, twenty-three".