1721129 has 8 divisors (see below), whose sum is σ = 1784328. Its totient is φ = 1658880.

The previous prime is 1721123. The next prime is 1721143. The reversal of 1721129 is 9211271.

It can be written as a sum of positive squares in 4 ways, for example, as 565504 + 1155625 = 752^2 + 1075^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1721129 - 2¹⁶ = 1655593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1721123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6569 + ... + 6825.

It is an arithmetic number, because the mean of its divisors is an integer number (223041).

2^1721129 is an apocalyptic number.

It is an amenable number.

1721129 is a deficient number, since it is larger than the sum of its proper divisors (63199).

1721129 is a wasteful number, since it uses less digits than its factorization.

1721129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 475.

The product of its digits is 252, while the sum is 23.

The square root of 1721129 is about 1311.9180614657. The cubic root of 1721129 is about 119.8407377972.

The spelling of 1721129 in words is "one million, seven hundred twenty-one thousand, one hundred twenty-nine".