123211531 has 2 divisors, whose sum is σ = 123211532. Its totient is φ = 123211530.

The previous prime is 123211507. The next prime is 123211547. The reversal of 123211531 is 135112321.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 123211531 - 2¹¹ = 123209483 is a prime.

It is a super-2 number, since 2×123211531² = 30362162742727922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 123211499 and 123211508.

It is not a weakly prime, because it can be changed into another prime (123211031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61605765 + 61605766.

It is an arithmetic number, because the mean of its divisors is an integer number (61605766).

Almost surely, 2^123211531 is an apocalyptic number.

123211531 is a deficient number, since it is larger than the sum of its proper divisors (1).

123211531 is an equidigital number, since it uses as much as digits as its factorization.

123211531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 180, while the sum is 19.

The square root of 123211531 is about 11100.0689637497. The cubic root of 123211531 is about 497.6039105191.

Adding to 123211531 its reverse (135112321), we get a palindrome (258323852).

The spelling of 123211531 in words is "one hundred twenty-three million, two hundred eleven thousand, five hundred thirty-one".