123551 has 2 divisors, whose sum is σ = 123552. Its totient is φ = 123550.

The previous prime is 123547. The next prime is 123553. The reversal of 123551 is 155321.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 123551 - 2² = 123547 is a prime.

Together with 123553, 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 (123553) 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, 61775 + 61776.

It is an arithmetic number, because the mean of its divisors is an integer number (61776).

2¹²³⁵⁵¹ is an apocalyptic number.

123551 is a deficient number, since it is larger than the sum of its proper divisors (1).

123551 is an equidigital number, since it uses as much as digits as its factorization.

123551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 150, while the sum is 17.

The square root of 123551 is about 351.4982219016. The cubic root of 123551 is about 49.8060486301.

Adding to 123551 its reverse (155321), we get a palindrome (278872).

The spelling of 123551 in words is "one hundred twenty-three thousand, five hundred fifty-one".