1609635997 has 4 divisors (see below), whose sum is σ = 1616544540. Its totient is φ = 1602727456.

The previous prime is 1609635983. The next prime is 1609636001. The reversal of 1609635997 is 7995369061.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 90897156 + 1518738841 = 9534^2 + 38971^2 .

It is a cyclic number.

It is not a de Polignac number, because 1609635997 - 2⁷ = 1609635869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1609635947) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3453922 + ... + 3454387.

It is an arithmetic number, because the mean of its divisors is an integer number (404136135).

Almost surely, 2^1609635997 is an apocalyptic number.

It is an amenable number.

1609635997 is a deficient number, since it is larger than the sum of its proper divisors (6908543).

1609635997 is an equidigital number, since it uses as much as digits as its factorization.

1609635997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6908542.

The product of its (nonzero) digits is 2755620, while the sum is 55.

The square root of 1609635997 is about 40120.2691541321. The cubic root of 1609635997 is about 1171.9503829263.

The spelling of 1609635997 in words is "one billion, six hundred nine million, six hundred thirty-five thousand, nine hundred ninety-seven".