123137521 has 4 divisors (see below), whose sum is σ = 132609652. Its totient is φ = 113665392.

The previous prime is 123137519. The next prime is 123137527. The reversal of 123137521 is 125731321.

It is a happy number.

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 64400625 + 58736896 = 8025^2 + 7664^2 .

It is a cyclic number.

It is not a de Polignac number, because 123137521 - 2¹ = 123137519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123137527) 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, 4736046 + ... + 4736071.

It is an arithmetic number, because the mean of its divisors is an integer number (33152413).

Almost surely, 2^123137521 is an apocalyptic number.

It is an amenable number.

123137521 is a deficient number, since it is larger than the sum of its proper divisors (9472131).

123137521 is an equidigital number, since it uses as much as digits as its factorization.

123137521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9472130.

The product of its digits is 1260, while the sum is 25.

The square root of 123137521 is about 11096.7346999016. The cubic root of 123137521 is about 497.5042579368.

Adding to 123137521 its reverse (125731321), we get a palindrome (248868842).

The spelling of 123137521 in words is "one hundred twenty-three million, one hundred thirty-seven thousand, five hundred twenty-one".