123643665 has 40 divisors (see below), whose sum is σ = 222489960. Its totient is φ = 65691648.

The previous prime is 123643661. The next prime is 123643673. The reversal of 123643665 is 566346321.

123643665 is a `hidden beast` number, since 1 + 2 + 3 + 643 + 6 + 6 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 14837904 + 108805761 = 3852^2 + 10431^2 .

It is not a de Polignac number, because 123643665 - 2² = 123643661 is a prime.

It is not an unprimeable number, because it can be changed into a prime (123643661) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 160401 + ... + 161169.

It is an arithmetic number, because the mean of its divisors is an integer number (5562249).

Almost surely, 2^123643665 is an apocalyptic number.

123643665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

123643665 is a deficient number, since it is larger than the sum of its proper divisors (98846295).

123643665 is an equidigital number, since it uses as much as digits as its factorization.

123643665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1183 (or 1174 counting only the distinct ones).

The product of its digits is 77760, while the sum is 36.

The square root of 123643665 is about 11119.5173006745. The cubic root of 123643665 is about 498.1849726572.

Adding to 123643665 its reverse (566346321), we get a palindrome (689989986).

The spelling of 123643665 in words is "one hundred twenty-three million, six hundred forty-three thousand, six hundred sixty-five".