81323805 has 8 divisors (see below), whose sum is σ = 130118112. Its totient is φ = 43372688.

The previous prime is 81323777. The next prime is 81323807. The reversal of 81323805 is 50832318.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 81323805 - 2⁵ = 81323773 is a prime.

It is a super-2 number, since 2×81323805² = 13227122519356050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81323807) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2710779 + ... + 2710808.

It is an arithmetic number, because the mean of its divisors is an integer number (16264764).

Almost surely, 2^81323805 is an apocalyptic number.

It is an amenable number.

81323805 is a deficient number, since it is larger than the sum of its proper divisors (48794307).

81323805 is a wasteful number, since it uses less digits than its factorization.

81323805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5421595.

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 81323805 is about 9017.9712241723. The cubic root of 81323805 is about 433.2506571397.

It can be divided in two parts, 81323 and 805, that added together give a palindrome (82128).

The spelling of 81323805 in words is "eighty-one million, three hundred twenty-three thousand, eight hundred five".