81006923 has 4 divisors (see below), whose sum is σ = 81037680. Its totient is φ = 80976168.

The previous prime is 81006917. The next prime is 81006967. The reversal of 81006923 is 32960018.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81006923 - 2⁴ = 81006907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81006973) 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, 11015 + ... + 16832.

It is an arithmetic number, because the mean of its divisors is an integer number (20259420).

Almost surely, 2^81006923 is an apocalyptic number.

81006923 is a deficient number, since it is larger than the sum of its proper divisors (30757).

81006923 is a wasteful number, since it uses less digits than its factorization.

81006923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30756.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 81006923 is about 9000.3846028934. The cubic root of 81006923 is about 432.6871975235.

The spelling of 81006923 in words is "eighty-one million, six thousand, nine hundred twenty-three".