1721147 has 2 divisors, whose sum is σ = 1721148. Its totient is φ = 1721146.

The previous prime is 1721143. The next prime is 1721149. The reversal of 1721147 is 7411271.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1721147 - 2² = 1721143 is a prime.

It is a super-3 number, since 3×1721147³ = 15295903933354330569, which contains 333 as substring.

Together with 1721149, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1721143) 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, 860573 + 860574.

It is an arithmetic number, because the mean of its divisors is an integer number (860574).

2^1721147 is an apocalyptic number.

1721147 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721147 is an equidigital number, since it uses as much as digits as its factorization.

1721147 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 392, while the sum is 23.

The square root of 1721147 is about 1311.9249216323. The cubic root of 1721147 is about 119.8411555706.

The spelling of 1721147 in words is "one million, seven hundred twenty-one thousand, one hundred forty-seven".