1211531 has 2 divisors, whose sum is σ = 1211532. Its totient is φ = 1211530.

The previous prime is 1211503. The next prime is 1211537. The reversal of 1211531 is 1351121.

It is a strong prime.

It is an emirp because it is prime and its reverse (1351121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1211531 - 2¹⁸ = 949387 is a prime.

It is a super-2 number, since 2×1211531² = 2935614727922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1211537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605765 + 605766.

It is an arithmetic number, because the mean of its divisors is an integer number (605766).

2^1211531 is an apocalyptic number.

1211531 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211531 is an equidigital number, since it uses as much as digits as its factorization.

1211531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30, while the sum is 14.

The square root of 1211531 is about 1100.6956890985. The cubic root of 1211531 is about 106.6051479033.

Adding to 1211531 its reverse (1351121), we get a palindrome (2562652).

The spelling of 1211531 in words is "one million, two hundred eleven thousand, five hundred thirty-one".