123205515 has 16 divisors (see below), whose sum is σ = 197721888. Its totient is φ = 65511936.

The previous prime is 123205513. The next prime is 123205517. The reversal of 123205515 is 515502321.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (123205513) and next prime (123205517).

It is not a de Polignac number, because 123205515 - 2¹ = 123205513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (123205513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7132 + ... + 17241.

It is an arithmetic number, because the mean of its divisors is an integer number (12357618).

Almost surely, 2^123205515 is an apocalyptic number.

123205515 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

123205515 is a deficient number, since it is larger than the sum of its proper divisors (74516373).

123205515 is a wasteful number, since it uses less digits than its factorization.

123205515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24718.

The product of its (nonzero) digits is 1500, while the sum is 24.

The square root of 123205515 is about 11099.7979711344. The cubic root of 123205515 is about 497.5958116185.

Adding to 123205515 its reverse (515502321), we get a palindrome (638707836).

The spelling of 123205515 in words is "one hundred twenty-three million, two hundred five thousand, five hundred fifteen".