137521 has 4 divisors (see below), whose sum is σ = 138852. Its totient is φ = 136192.

The previous prime is 137519. The next prime is 137537. The reversal of 137521 is 125731.

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 18496 + 119025 = 136^2 + 345^2 .

It is a cyclic number.

It is not a de Polignac number, because 137521 - 2¹ = 137519 is a prime.

It is a d-powerful number, because it can be written as 1 + 3¹⁰ + 5⁷ + 7³ + 2 + 1 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (137321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 496 + ... + 721.

It is an arithmetic number, because the mean of its divisors is an integer number (34713).

2¹³⁷⁵²¹ is an apocalyptic number.

It is an amenable number.

137521 is a deficient number, since it is larger than the sum of its proper divisors (1331).

137521 is a wasteful number, since it uses less digits than its factorization.

137521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1330.

The product of its digits is 210, while the sum is 19.

The square root of 137521 is about 370.8382396679. The cubic root of 137521 is about 51.6166332612.

Adding to 137521 its product of digits (210), we get a palindrome (137731).

The spelling of 137521 in words is "one hundred thirty-seven thousand, five hundred twenty-one".