1721393 has 4 divisors (see below), whose sum is σ = 1729140. Its totient is φ = 1713648.

The previous prime is 1721383. The next prime is 1721407. The reversal of 1721393 is 3931271.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3931271 = 19 ⋅206909.

It can be written as a sum of positive squares in 2 ways, for example, as 1607824 + 113569 = 1268^2 + 337^2 .

It is a cyclic number.

It is not a de Polignac number, because 1721393 - 2¹² = 1717297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1721323) 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, 3530 + ... + 3987.

It is an arithmetic number, because the mean of its divisors is an integer number (432285).

2^1721393 is an apocalyptic number.

It is an amenable number.

1721393 is a deficient number, since it is larger than the sum of its proper divisors (7747).

1721393 is an equidigital number, since it uses as much as digits as its factorization.

1721393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7746.

The product of its digits is 1134, while the sum is 26.

The square root of 1721393 is about 1312.0186736476. The cubic root of 1721393 is about 119.8468648485.

The spelling of 1721393 in words is "one million, seven hundred twenty-one thousand, three hundred ninety-three".