423721 has 4 divisors (see below), whose sum is σ = 426244. Its totient is φ = 421200.

The previous prime is 423713. The next prime is 423727. The reversal of 423721 is 127324.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 105625 + 318096 = 325^2 + 564^2 .

It is a cyclic number.

It is not a de Polignac number, because 423721 - 2³ = 423713 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (423727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 990 + ... + 1351.

It is an arithmetic number, because the mean of its divisors is an integer number (106561).

2⁴²³⁷²¹ is an apocalyptic number.

It is an amenable number.

423721 is a deficient number, since it is larger than the sum of its proper divisors (2523).

423721 is a wasteful number, since it uses less digits than its factorization.

423721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2522.

The product of its digits is 336, while the sum is 19.

The square root of 423721 is about 650.9385531677. The cubic root of 423721 is about 75.1092334228.

The spelling of 423721 in words is "four hundred twenty-three thousand, seven hundred twenty-one", and thus it is an iban number.