81670223 has 4 divisors (see below), whose sum is σ = 81865560. Its totient is φ = 81474888.

The previous prime is 81670207. The next prime is 81670229. The reversal of 81670223 is 32207618.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32207618 = 2 ⋅16103809.

It is a cyclic number.

It is not a de Polignac number, because 81670223 - 2⁴ = 81670207 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 (81670229) 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, 97040 + ... + 97877.

It is an arithmetic number, because the mean of its divisors is an integer number (20466390).

Almost surely, 2^81670223 is an apocalyptic number.

81670223 is a deficient number, since it is larger than the sum of its proper divisors (195337).

81670223 is a wasteful number, since it uses less digits than its factorization.

81670223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195336.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 81670223 is about 9037.1579050053. The cubic root of 81670223 is about 433.8649636163.

The spelling of 81670223 in words is "eighty-one million, six hundred seventy thousand, two hundred twenty-three".