1721407 has 2 divisors, whose sum is σ = 1721408. Its totient is φ = 1721406.

The previous prime is 1721383. The next prime is 1721417. The reversal of 1721407 is 7041271.

It is a strong prime.

It is an emirp because it is prime and its reverse (7041271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1721407 - 2¹¹ = 1719359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1721417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860703 + 860704.

It is an arithmetic number, because the mean of its divisors is an integer number (860704).

2^1721407 is an apocalyptic number.

1721407 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721407 is an equidigital number, since it uses as much as digits as its factorization.

1721407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 392, while the sum is 22.

The square root of 1721407 is about 1312.0240089267. The cubic root of 1721407 is about 119.8471897504.

Adding to 1721407 its reverse (7041271), we get a palindrome (8762678).

The spelling of 1721407 in words is "one million, seven hundred twenty-one thousand, four hundred seven".