1661313133 has 2 divisors, whose sum is σ = 1661313134. Its totient is φ = 1661313132.

The previous prime is 1661313131. The next prime is 1661313179. The reversal of 1661313133 is 3313131661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1372924809 + 288388324 = 37053^2 + 16982^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661313133 - 2¹ = 1661313131 is a prime.

It is a super-2 number, since 2×1661313133² = 5519922651756551378, which contains 22 as substring.

Together with 1661313131, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1661313131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830656566 + 830656567.

It is an arithmetic number, because the mean of its divisors is an integer number (830656567).

Almost surely, 2^1661313133 is an apocalyptic number.

It is an amenable number.

1661313133 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661313133 is an equidigital number, since it uses as much as digits as its factorization.

1661313133 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2916, while the sum is 28.

The square root of 1661313133 is about 40759.2091802577. The cubic root of 1661313133 is about 1184.3602766395.

Adding to 1661313133 its reverse (3313131661), we get a palindrome (4974444794).

The spelling of 1661313133 in words is "one billion, six hundred sixty-one million, three hundred thirteen thousand, one hundred thirty-three".