123040021 has 8 divisors (see below), whose sum is σ = 132592824. Its totient is φ = 113499840.

The previous prime is 123040003. The next prime is 123040037. The reversal of 123040021 is 120040321.

It can be written as a sum of positive squares in 4 ways, for example, as 21252100 + 101787921 = 4610^2 + 10089^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 123040021 - 2⁹ = 123039509 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a junction number, because it is equal to n+sod(n) for n = 123039983 and 123040010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123040081) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30291 + ... + 34111.

It is an arithmetic number, because the mean of its divisors is an integer number (16574103).

Almost surely, 2^123040021 is an apocalyptic number.

It is an amenable number.

123040021 is a deficient number, since it is larger than the sum of its proper divisors (9552803).

123040021 is a wasteful number, since it uses less digits than its factorization.

123040021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6311.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 123040021 is about 11092.3406456888. The cubic root of 123040021 is about 497.3729156975.

Adding to 123040021 its reverse (120040321), we get a palindrome (243080342).

The spelling of 123040021 in words is "one hundred twenty-three million, forty thousand, twenty-one".