123135551 has 16 divisors (see below), whose sum is σ = 154049280. Its totient is φ = 95618880.

The previous prime is 123135547. The next prime is 123135553. The reversal of 123135551 is 155531321.

It is a happy number.

It is not a de Polignac number, because 123135551 - 2² = 123135547 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 123135551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123135553) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21035 + ... + 26243.

It is an arithmetic number, because the mean of its divisors is an integer number (9628080).

Almost surely, 2^123135551 is an apocalyptic number.

123135551 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

123135551 is a deficient number, since it is larger than the sum of its proper divisors (30913729).

123135551 is a wasteful number, since it uses less digits than its factorization.

123135551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5534.

The product of its digits is 2250, while the sum is 26.

The square root of 123135551 is about 11096.6459346958. The cubic root of 123135551 is about 497.5016048365.

Adding to 123135551 its reverse (155531321), we get a palindrome (278666872).

The spelling of 123135551 in words is "one hundred twenty-three million, one hundred thirty-five thousand, five hundred fifty-one".