1231511 has 2 divisors, whose sum is σ = 1231512. Its totient is φ = 1231510.

The previous prime is 1231487. The next prime is 1231513. The reversal of 1231511 is 1151321.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1231511 is a prime.

Together with 1231513, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231513) by changing a digit.

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

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615755 + 615756.

It is an arithmetic number, because the mean of its divisors is an integer number (615756).

2^1231511 is an apocalyptic number.

1231511 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231511 is an equidigital number, since it uses as much as digits as its factorization.

1231511 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 1231511 is about 1109.7346529689. The cubic root of 1231511 is about 107.1879829386.

Adding to 1231511 its reverse (1151321), we get a palindrome (2382832).

The spelling of 1231511 in words is "one million, two hundred thirty-one thousand, five hundred eleven".