81823901 has 4 divisors (see below), whose sum is σ = 82211904. Its totient is φ = 81435900.

The previous prime is 81823871. The next prime is 81823913. The reversal of 81823901 is 10932818.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81823901 - 2²⁶ = 14715037 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 (81823991) 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, 193685 + ... + 194106.

It is an arithmetic number, because the mean of its divisors is an integer number (20552976).

Almost surely, 2^81823901 is an apocalyptic number.

It is an amenable number.

81823901 is a deficient number, since it is larger than the sum of its proper divisors (388003).

81823901 is a wasteful number, since it uses less digits than its factorization.

81823901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 388002.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 81823901 is about 9045.6564714785. The cubic root of 81823901 is about 434.1369261514.

The spelling of 81823901 in words is "eighty-one million, eight hundred twenty-three thousand, nine hundred one".