664172423 has 4 divisors (see below), whose sum is σ = 664617000. Its totient is φ = 663727848.

The previous prime is 664172419. The next prime is 664172447. The reversal of 664172423 is 324271466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 324271466 = 2 ⋅162135733.

It is a cyclic number.

It is not a de Polignac number, because 664172423 - 2² = 664172419 is a prime.

It is a super-2 number, since 2×664172423² = 882250014947381858, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664102423) 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, 220040 + ... + 223037.

It is an arithmetic number, because the mean of its divisors is an integer number (166154250).

Almost surely, 2^664172423 is an apocalyptic number.

664172423 is a deficient number, since it is larger than the sum of its proper divisors (444577).

664172423 is a wasteful number, since it uses less digits than its factorization.

664172423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444576.

The product of its digits is 48384, while the sum is 35.

The square root of 664172423 is about 25771.5428913366. The cubic root of 664172423 is about 872.4896419435.

The spelling of 664172423 in words is "six hundred sixty-four million, one hundred seventy-two thousand, four hundred twenty-three".