1331253561 has 16 divisors (see below), whose sum is σ = 2050273728. Its totient is φ = 759360000.

The previous prime is 1331253533. The next prime is 1331253577. The reversal of 1331253561 is 1653521331.

It is not a de Polignac number, because 1331253561 - 2¹⁹ = 1330729273 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1331253461) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1185940 + ... + 1187061.

It is an arithmetic number, because the mean of its divisors is an integer number (128142108).

Almost surely, 2^1331253561 is an apocalyptic number.

1331253561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1331253561 is a deficient number, since it is larger than the sum of its proper divisors (719020167).

1331253561 is a wasteful number, since it uses less digits than its factorization.

1331253561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2373032.

The product of its digits is 8100, while the sum is 30.

The square root of 1331253561 is about 36486.3475974233. The cubic root of 1331253561 is about 1100.0698470800.

Adding to 1331253561 its reverse (1653521331), we get a palindrome (2984774892).

The spelling of 1331253561 in words is "one billion, three hundred thirty-one million, two hundred fifty-three thousand, five hundred sixty-one".