137730521 has 4 divisors (see below), whose sum is σ = 141089844. Its totient is φ = 134371200.

The previous prime is 137730503. The next prime is 137730529. The reversal of 137730521 is 125037731.

137730521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 52722121 + 85008400 = 7261^2 + 9220^2 .

It is a cyclic number.

It is not a de Polignac number, because 137730521 - 2²² = 133536217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (137730529) 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, 1679600 + ... + 1679681.

It is an arithmetic number, because the mean of its divisors is an integer number (35272461).

Almost surely, 2^137730521 is an apocalyptic number.

It is an amenable number.

137730521 is a deficient number, since it is larger than the sum of its proper divisors (3359323).

137730521 is an equidigital number, since it uses as much as digits as its factorization.

137730521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3359322.

The product of its (nonzero) digits is 4410, while the sum is 29.

The square root of 137730521 is about 11735.8647316676. The cubic root of 137730521 is about 516.4283357714.

The spelling of 137730521 in words is "one hundred thirty-seven million, seven hundred thirty thousand, five hundred twenty-one".