1605650009 has 2 divisors, whose sum is σ = 1605650010. Its totient is φ = 1605650008.

The previous prime is 1605649973. The next prime is 1605650027. The reversal of 1605650009 is 9000565061.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1453744384 + 151905625 = 38128^2 + 12325^2 .

It is an emirp because it is prime and its reverse (9000565061) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1605650009 - 2⁸ = 1605649753 is a prime.

It is a super-2 number, since 2×1605650009² = 5156223902803400162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1605650069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802825004 + 802825005.

It is an arithmetic number, because the mean of its divisors is an integer number (802825005).

Almost surely, 2^1605650009 is an apocalyptic number.

It is an amenable number.

1605650009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1605650009 is an equidigital number, since it uses as much as digits as its factorization.

1605650009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8100, while the sum is 32.

The square root of 1605650009 is about 40070.5628735110. The cubic root of 1605650009 is about 1170.9822051430.

The spelling of 1605650009 in words is "one billion, six hundred five million, six hundred fifty thousand, nine".