1661204326 has 4 divisors (see below), whose sum is σ = 2491806492. Its totient is φ = 830602162.

The previous prime is 1661204297. The next prime is 1661204327. The reversal of 1661204326 is 6234021661.

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

It is a super-2 number, since 2×1661204326² = 5519199625442228552, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661204327) 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, 415301080 + ... + 415301083.

It is an arithmetic number, because the mean of its divisors is an integer number (622951623).

Almost surely, 2^1661204326 is an apocalyptic number.

1661204326 is a deficient number, since it is larger than the sum of its proper divisors (830602166).

1661204326 is an equidigital number, since it uses as much as digits as its factorization.

1661204326 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 830602165.

The product of its (nonzero) digits is 10368, while the sum is 31.

The square root of 1661204326 is about 40757.8744048313. The cubic root of 1661204326 is about 1184.3344196834.

Adding to 1661204326 its reverse (6234021661), we get a palindrome (7895225987).

The spelling of 1661204326 in words is "one billion, six hundred sixty-one million, two hundred four thousand, three hundred twenty-six".