137321813 has 4 divisors (see below), whose sum is σ = 138324300. Its totient is φ = 136319328.

The previous prime is 137321809. The next prime is 137321831. The reversal of 137321813 is 318123731.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 318123731 = 1867 ⋅170393.

It can be written as a sum of positive squares in 2 ways, for example, as 100440484 + 36881329 = 10022^2 + 6073^2 .

It is a cyclic number.

It is not a de Polignac number, because 137321813 - 2² = 137321809 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (137321213) 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, 501038 + ... + 501311.

It is an arithmetic number, because the mean of its divisors is an integer number (34581075).

Almost surely, 2^137321813 is an apocalyptic number.

It is an amenable number.

137321813 is a deficient number, since it is larger than the sum of its proper divisors (1002487).

137321813 is a wasteful number, since it uses less digits than its factorization.

137321813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1002486.

The product of its digits is 3024, while the sum is 29.

The square root of 137321813 is about 11718.4390172070. The cubic root of 137321813 is about 515.9170051100.

The spelling of 137321813 in words is "one hundred thirty-seven million, three hundred twenty-one thousand, eight hundred thirteen".