123136640 has 64 divisors (see below), whose sum is σ = 321153120. Its totient is φ = 44774400.

The previous prime is 123136621. The next prime is 123136679. The reversal of 123136640 is 46631321.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×123136640² = 30325264220979200, which contains 22 as substring.

It is an unprimeable number.

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, 1706 + ... + 15785.

Almost surely, 2^123136640 is an apocalyptic number.

123136640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 123136640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160576560).

123136640 is an abundant number, since it is smaller than the sum of its proper divisors (198016480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

123136640 is a wasteful number, since it uses less digits than its factorization.

123136640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17521 (or 17509 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 123136640 is about 11096.6950034684. The cubic root of 123136640 is about 497.5030714523.

Adding to 123136640 its reverse (46631321), we get a palindrome (169767961).

The spelling of 123136640 in words is "one hundred twenty-three million, one hundred thirty-six thousand, six hundred forty".