1721801 has 4 divisors (see below), whose sum is σ = 1731600. Its totient is φ = 1712004.

The previous prime is 1721779. The next prime is 1721807. The reversal of 1721801 is 1081271.

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: 1081271 = 19 ⋅56909.

It is a cyclic number.

It is not a de Polignac number, because 1721801 - 2¹⁰ = 1720777 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1721807) 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, 4631 + ... + 4988.

It is an arithmetic number, because the mean of its divisors is an integer number (432900).

2^1721801 is an apocalyptic number.

It is an amenable number.

1721801 is a deficient number, since it is larger than the sum of its proper divisors (9799).

1721801 is an equidigital number, since it uses as much as digits as its factorization.

1721801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9798.

The product of its (nonzero) digits is 112, while the sum is 20.

The square root of 1721801 is about 1312.1741500274. The cubic root of 1721801 is about 119.8563326958.

The spelling of 1721801 in words is "one million, seven hundred twenty-one thousand, eight hundred one".