1721441 has 2 divisors, whose sum is σ = 1721442. Its totient is φ = 1721440.

The previous prime is 1721417. The next prime is 1721449. The reversal of 1721441 is 1441271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1700416 + 21025 = 1304^2 + 145^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1721441 is a prime.

It is a Sophie Germain prime.

It is a pancake number, because a pancake can be divided into 1721441 parts by 1855 straight cuts.

It is a Curzon number.

It is equal to p₁₂₉₆₂₀ and since 1721441 and 129620 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (1721449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860720 + 860721.

It is an arithmetic number, because the mean of its divisors is an integer number (860721).

2^1721441 is an apocalyptic number.

It is an amenable number.

1721441 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721441 is an equidigital number, since it uses as much as digits as its factorization.

1721441 is an evil number, because the sum of its binary digits is even.

The product of its digits is 224, while the sum is 20.

The square root of 1721441 is about 1312.0369659427. The cubic root of 1721441 is about 119.8479787906.

The spelling of 1721441 in words is "one million, seven hundred twenty-one thousand, four hundred forty-one".