20691173 has 4 divisors (see below), whose sum is σ = 20700288. Its totient is φ = 20682060.

The previous prime is 20691149. The next prime is 20691197. The reversal of 20691173 is 37119602.

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, and also a brilliant number, because the two primes have the same length.

It is an interprime number because it is at equal distance from previous prime (20691149) and next prime (20691197).

It is a cyclic number.

It is not a de Polignac number, because 20691173 - 2⁶ = 20691109 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 (20691113) 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, 1868 + ... + 6698.

It is an arithmetic number, because the mean of its divisors is an integer number (5175072).

Almost surely, 2^20691173 is an apocalyptic number.

It is an amenable number.

20691173 is a deficient number, since it is larger than the sum of its proper divisors (9115).

20691173 is an equidigital number, since it uses as much as digits as its factorization.

20691173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9114.

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 20691173 is about 4548.7551044214. The cubic root of 20691173 is about 274.5333042981.

The spelling of 20691173 in words is "twenty million, six hundred ninety-one thousand, one hundred seventy-three".