81323673 has 4 divisors (see below), whose sum is σ = 108431568. Its totient is φ = 54215780.

The previous prime is 81323659. The next prime is 81323681. The reversal of 81323673 is 37632318.

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 81323673 - 2⁶ = 81323609 is a prime.

It is a super-2 number, since 2×81323673² = 13227079580421858, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81323573) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13553943 + ... + 13553948.

It is an arithmetic number, because the mean of its divisors is an integer number (27107892).

Almost surely, 2^81323673 is an apocalyptic number.

It is an amenable number.

81323673 is a deficient number, since it is larger than the sum of its proper divisors (27107895).

81323673 is a wasteful number, since it uses less digits than its factorization.

81323673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27107894.

The product of its digits is 18144, while the sum is 33.

The square root of 81323673 is about 9017.9639054501. The cubic root of 81323673 is about 433.2504227306.

The spelling of 81323673 in words is "eighty-one million, three hundred twenty-three thousand, six hundred seventy-three".