1721215 has 4 divisors (see below), whose sum is σ = 2065464. Its totient is φ = 1376968.

The previous prime is 1721201. The next prime is 1721227. The reversal of 1721215 is 5121271.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1721215 - 2⁵ = 1721183 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1721192 and 1721201.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 172117 + ... + 172126.

It is an arithmetic number, because the mean of its divisors is an integer number (516366).

2^1721215 is an apocalyptic number.

1721215 is a deficient number, since it is larger than the sum of its proper divisors (344249).

1721215 is an equidigital number, since it uses as much as digits as its factorization.

1721215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344248.

The product of its digits is 140, while the sum is 19.

The square root of 1721215 is about 1311.9508374935. The cubic root of 1721215 is about 119.8427337994.

Adding to 1721215 its reverse (5121271), we get a palindrome (6842486).

It can be divided in two parts, 1721 and 215, that added together give a square (1936 = 44²).

The spelling of 1721215 in words is "one million, seven hundred twenty-one thousand, two hundred fifteen".