123131021 has 4 divisors (see below), whose sum is σ = 132602652. Its totient is φ = 113659392.

The previous prime is 123131009. The next prime is 123131033. The reversal of 123131021 is 120131321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120131321 = 5717 ⋅21013.

It is an interprime number because it is at equal distance from previous prime (123131009) and next prime (123131033).

It can be written as a sum of positive squares in 2 ways, for example, as 74200996 + 48930025 = 8614^2 + 6995^2 .

It is a cyclic number.

It is not a de Polignac number, because 123131021 - 2⁶ = 123130957 is a prime.

It is a super-2 number, since 2×123131021² = 30322496665004882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 123130987 and 123131005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123131521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4735796 + ... + 4735821.

It is an arithmetic number, because the mean of its divisors is an integer number (33150663).

Almost surely, 2^123131021 is an apocalyptic number.

It is an amenable number.

123131021 is a deficient number, since it is larger than the sum of its proper divisors (9471631).

123131021 is an equidigital number, since it uses as much as digits as its factorization.

123131021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9471630.

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

The square root of 123131021 is about 11096.4418170871. The cubic root of 123131021 is about 497.4955039450.

Adding to 123131021 its reverse (120131321), we get a palindrome (243262342).

The spelling of 123131021 in words is "one hundred twenty-three million, one hundred thirty-one thousand, twenty-one".