137021 has 4 divisors (see below), whose sum is σ = 138972. Its totient is φ = 135072.

The previous prime is 136999. The next prime is 137029. The reversal of 137021 is 120731.

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 81796 + 55225 = 286^2 + 235^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-137021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 136987 and 137005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (137029) 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, 866 + ... + 1011.

It is an arithmetic number, because the mean of its divisors is an integer number (34743).

2¹³⁷⁰²¹ is an apocalyptic number.

It is an amenable number.

137021 is a deficient number, since it is larger than the sum of its proper divisors (1951).

137021 is an equidigital number, since it uses as much as digits as its factorization.

137021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1950.

The product of its (nonzero) digits is 42, while the sum is 14.

The square root of 137021 is about 370.1634773988. The cubic root of 137021 is about 51.5540012317.

Adding to 137021 its reverse (120731), we get a palindrome (257752).

Subtracting from 137021 its reverse (120731), we obtain a triangular number (16290 = T₁₈₀).

The spelling of 137021 in words is "one hundred thirty-seven thousand, twenty-one".