1640609 has 2 divisors, whose sum is σ = 1640610. Its totient is φ = 1640608.

The previous prime is 1640599. The next prime is 1640621. The reversal of 1640609 is 9060461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1638400 + 2209 = 1280^2 + 47^2 .

It is an emirp because it is prime and its reverse (9060461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1640609 - 2¹² = 1636513 is a prime.

It is a plaindrome in base 13.

It is not a weakly prime, because it can be changed into another prime (1640689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820304 + 820305.

It is an arithmetic number, because the mean of its divisors is an integer number (820305).

2^1640609 is an apocalyptic number.

It is an amenable number.

1640609 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640609 is an equidigital number, since it uses as much as digits as its factorization.

1640609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 1640609 is about 1280.8625999693. The cubic root of 1640609 is about 117.9419661004.

The spelling of 1640609 in words is "one million, six hundred forty thousand, six hundred nine".