1661489 has 2 divisors, whose sum is σ = 1661490. Its totient is φ = 1661488.

The previous prime is 1661479. The next prime is 1661503. The reversal of 1661489 is 9841661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1311025 + 350464 = 1145^2 + 592^2 .

It is an emirp because it is prime and its reverse (9841661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1661489 - 2¹⁶ = 1595953 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1661479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830744 + 830745.

It is an arithmetic number, because the mean of its divisors is an integer number (830745).

2^1661489 is an apocalyptic number.

It is an amenable number.

1661489 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661489 is an equidigital number, since it uses as much as digits as its factorization.

1661489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 35.

The square root of 1661489 is about 1288.9875872172. The cubic root of 1661489 is about 118.4402067384.

The spelling of 1661489 in words is "one million, six hundred sixty-one thousand, four hundred eighty-nine".