123216551 has 8 divisors (see below), whose sum is σ = 125259264. Its totient is φ = 121179960.

The previous prime is 123216547. The next prime is 123216553. The reversal of 123216551 is 155612321.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 123216551 - 2² = 123216547 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 123216551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123216553) 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 in 7 ways as a sum of consecutive naturals, for example, 56756 + ... + 58886.

It is an arithmetic number, because the mean of its divisors is an integer number (15657408).

Almost surely, 2^123216551 is an apocalyptic number.

123216551 is a deficient number, since it is larger than the sum of its proper divisors (2042713).

123216551 is an equidigital number, since it uses as much as digits as its factorization.

123216551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3061.

The product of its digits is 1800, while the sum is 26.

The square root of 123216551 is about 11100.2950861678. The cubic root of 123216551 is about 497.6106683761.

Adding to 123216551 its reverse (155612321), we get a palindrome (278828872).

The spelling of 123216551 in words is "one hundred twenty-three million, two hundred sixteen thousand, five hundred fifty-one".