123031010021 has 4 divisors (see below), whose sum is σ = 126356172492. Its totient is φ = 119705847552.

The previous prime is 123031009999. The next prime is 123031010041. The reversal of 123031010021 is 120010130321.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 106412964100 + 16618045921 = 326210^2 + 128911^2 .

It is a cyclic number.

It is not a de Polignac number, because 123031010021 - 2⁶ = 123031009957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 123031009978 and 123031010005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123031010041) 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 3 ways as a sum of consecutive naturals, for example, 1662581180 + ... + 1662581253.

It is an arithmetic number, because the mean of its divisors is an integer number (31589043123).

Almost surely, 2^123031010021 is an apocalyptic number.

It is an amenable number.

123031010021 is a deficient number, since it is larger than the sum of its proper divisors (3325162471).

123031010021 is an equidigital number, since it uses as much as digits as its factorization.

123031010021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3325162470.

The product of its (nonzero) digits is 36, while the sum is 14.

Adding to 123031010021 its reverse (120010130321), we get a palindrome (243041140342).

The spelling of 123031010021 in words is "one hundred twenty-three billion, thirty-one million, ten thousand, twenty-one".