20664173 has 4 divisors (see below), whose sum is σ = 20743008. Its totient is φ = 20585340.

The previous prime is 20664139. The next prime is 20664239. The reversal of 20664173 is 37146602.

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 an emirpimes, since its reverse is a distinct semiprime: 37146602 = 2 ⋅18573301.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20664173 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 (20664113) 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, 39023 + ... + 39548.

It is an arithmetic number, because the mean of its divisors is an integer number (5185752).

Almost surely, 2^20664173 is an apocalyptic number.

It is an amenable number.

20664173 is a deficient number, since it is larger than the sum of its proper divisors (78835).

20664173 is an equidigital number, since it uses as much as digits as its factorization.

20664173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78834.

The product of its (nonzero) digits is 6048, while the sum is 29.

The square root of 20664173 is about 4545.7862906212. The cubic root of 20664173 is about 274.4138390924.

The spelling of 20664173 in words is "twenty million, six hundred sixty-four thousand, one hundred seventy-three".