1331633261 has 6 divisors (see below), whose sum is σ = 1549042830. Its totient is φ = 1141399896.

The previous prime is 1331633257. The next prime is 1331633263. The reversal of 1331633261 is 1623361331.

It can be written as a sum of positive squares in only one way, i.e., 923795236 + 407838025 = 30394^2 + 20195^2 .

It is not a de Polignac number, because 1331633261 - 2² = 1331633257 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 (1331633263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13588046 + ... + 13588143.

It is an arithmetic number, because the mean of its divisors is an integer number (258173805).

Almost surely, 2^1331633261 is an apocalyptic number.

It is an amenable number.

1331633261 is a deficient number, since it is larger than the sum of its proper divisors (217409569).

1331633261 is an equidigital number, since it uses as much as digits as its factorization.

1331633261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27176203 (or 27176196 counting only the distinct ones).

The product of its digits is 5832, while the sum is 29.

The square root of 1331633261 is about 36491.5505425571. The cubic root of 1331633261 is about 1100.1744244066.

Adding to 1331633261 its reverse (1623361331), we get a palindrome (2954994592).

The spelling of 1331633261 in words is "one billion, three hundred thirty-one million, six hundred thirty-three thousand, two hundred sixty-one".