123217531 has 2 divisors, whose sum is σ = 123217532. Its totient is φ = 123217530.

The previous prime is 123217441. The next prime is 123217553. The reversal of 123217531 is 135712321.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (135712321) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123217531 is a prime.

It is a super-2 number, since 2×123217531² = 30365119891471922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 123217496 and 123217505.

It is not a weakly prime, because it can be changed into another prime (123217631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61608765 + 61608766.

It is an arithmetic number, because the mean of its divisors is an integer number (61608766).

Almost surely, 2^123217531 is an apocalyptic number.

123217531 is a deficient number, since it is larger than the sum of its proper divisors (1).

123217531 is an equidigital number, since it uses as much as digits as its factorization.

123217531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1260, while the sum is 25.

The square root of 123217531 is about 11100.3392290506. The cubic root of 123217531 is about 497.6119876176.

Adding to 123217531 its reverse (135712321), we get a palindrome (258929852).

The spelling of 123217531 in words is "one hundred twenty-three million, two hundred seventeen thousand, five hundred thirty-one".