1211530513 has 4 divisors (see below), whose sum is σ = 1212290740. Its totient is φ = 1210770288.

The previous prime is 1211530511. The next prime is 1211530549. The reversal of 1211530513 is 3150351121.

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 743543824 + 467986689 = 27268^2 + 21633^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211530513 - 2¹ = 1211530511 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1211530511) 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, 377718 + ... + 380911.

It is an arithmetic number, because the mean of its divisors is an integer number (303072685).

Almost surely, 2^1211530513 is an apocalyptic number.

It is an amenable number.

1211530513 is a deficient number, since it is larger than the sum of its proper divisors (760227).

1211530513 is an equidigital number, since it uses as much as digits as its factorization.

1211530513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 760226.

The product of its (nonzero) digits is 450, while the sum is 22.

The square root of 1211530513 is about 34807.0468870888. The cubic root of 1211530513 is about 1066.0513361927.

Adding to 1211530513 its reverse (3150351121), we get a palindrome (4361881634).

The spelling of 1211530513 in words is "one billion, two hundred eleven million, five hundred thirty thousand, five hundred thirteen".