123536721 has 32 divisors (see below), whose sum is σ = 210152448. Its totient is φ = 62677440.

The previous prime is 123536713. The next prime is 123536741. The reversal of 123536721 is 127635321.

It is not a de Polignac number, because 123536721 - 2³ = 123536713 is a prime.

It is a super-2 number, since 2×123536721² = 30522642870863682, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (123536701) 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 31 ways as a sum of consecutive naturals, for example, 3715 + ... + 16151.

It is an arithmetic number, because the mean of its divisors is an integer number (6567264).

Almost surely, 2^123536721 is an apocalyptic number.

123536721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

123536721 is a deficient number, since it is larger than the sum of its proper divisors (86615727).

123536721 is a wasteful number, since it uses less digits than its factorization.

123536721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12501.

The product of its digits is 7560, while the sum is 30.

The square root of 123536721 is about 11114.7074185513. The cubic root of 123536721 is about 498.0412983283.

The spelling of 123536721 in words is "one hundred twenty-three million, five hundred thirty-six thousand, seven hundred twenty-one".