451721 has 4 divisors (see below), whose sum is σ = 454212. Its totient is φ = 449232.

The previous prime is 451709. The next prime is 451723. The reversal of 451721 is 127154.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127154 = 2 ⋅63577.

It can be written as a sum of positive squares in 2 ways, for example, as 319225 + 132496 = 565^2 + 364^2 .

It is a cyclic number.

It is not a de Polignac number, because 451721 - 2⁶ = 451657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 451693 and 451702.

It is not an unprimeable number, because it can be changed into a prime (451723) 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, 950 + ... + 1343.

It is an arithmetic number, because the mean of its divisors is an integer number (113553).

2⁴⁵¹⁷²¹ is an apocalyptic number.

It is an amenable number.

451721 is a deficient number, since it is larger than the sum of its proper divisors (2491).

451721 is a wasteful number, since it uses less digits than its factorization.

451721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2490.

The product of its digits is 280, while the sum is 20.

The square root of 451721 is about 672.1019267938. The cubic root of 451721 is about 76.7285092280.

Adding to 451721 its reverse (127154), we get a palindrome (578875).

The spelling of 451721 in words is "four hundred fifty-one thousand, seven hundred twenty-one".