1789721 has 2 divisors, whose sum is σ = 1789722. Its totient is φ = 1789720.

The previous prime is 1789693. The next prime is 1789751. The reversal of 1789721 is 1279871.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1638400 + 151321 = 1280^2 + 389^2 .

It is an emirp because it is prime and its reverse (1279871) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1789721 - 2¹⁴ = 1773337 is a prime.

It is not a weakly prime, because it can be changed into another prime (1789751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 894860 + 894861.

It is an arithmetic number, because the mean of its divisors is an integer number (894861).

2^1789721 is an apocalyptic number.

It is an amenable number.

1789721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1789721 is an equidigital number, since it uses as much as digits as its factorization.

1789721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7056, while the sum is 35.

The square root of 1789721 is about 1337.8045447673. The cubic root of 1789721 is about 121.4120460622.

The spelling of 1789721 in words is "one million, seven hundred eighty-nine thousand, seven hundred twenty-one".