1721369 has 8 divisors (see below), whose sum is σ = 1963080. Its totient is φ = 1495296.

The previous prime is 1721347. The next prime is 1721371. The reversal of 1721369 is 9631271.

It can be written as a sum of positive squares in 4 ways, for example, as 250000 + 1471369 = 500^2 + 1213^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1721369 is a prime.

It is a super-2 number, since 2×1721369² = 5926222468322, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721339) 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, 3674 + ... + 4115.

It is an arithmetic number, because the mean of its divisors is an integer number (245385).

2^1721369 is an apocalyptic number.

It is an amenable number.

1721369 is a deficient number, since it is larger than the sum of its proper divisors (241711).

1721369 is a wasteful number, since it uses less digits than its factorization.

1721369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7819.

The product of its digits is 2268, while the sum is 29.

The square root of 1721369 is about 1312.0095274044. The cubic root of 1721369 is about 119.8463078697.

The spelling of 1721369 in words is "one million, seven hundred twenty-one thousand, three hundred sixty-nine".