137981537 has 4 divisors (see below), whose sum is σ = 146098116. Its totient is φ = 129864960.

The previous prime is 137981533. The next prime is 137981587. The reversal of 137981537 is 735189731.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 735189731 = 13399 ⋅54869.

It can be written as a sum of positive squares in 2 ways, for example, as 87628321 + 50353216 = 9361^2 + 7096^2 .

It is a cyclic number.

It is not a de Polignac number, because 137981537 - 2² = 137981533 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (137981533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4058264 + ... + 4058297.

It is an arithmetic number, because the mean of its divisors is an integer number (36524529).

Almost surely, 2^137981537 is an apocalyptic number.

137981537 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

137981537 is a deficient number, since it is larger than the sum of its proper divisors (8116579).

137981537 is an equidigital number, since it uses as much as digits as its factorization.

137981537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8116578.

The product of its digits is 158760, while the sum is 44.

The square root of 137981537 is about 11746.5542607183. The cubic root of 137981537 is about 516.7418782404.

The spelling of 137981537 in words is "one hundred thirty-seven million, nine hundred eighty-one thousand, five hundred thirty-seven".