137581681 has 4 divisors (see below), whose sum is σ = 138799332. Its totient is φ = 136364032.

The previous prime is 137581673. The next prime is 137581711. The reversal of 137581681 is 186185731.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 186185731 = 19 ⋅9799249.

It can be written as a sum of positive squares in 2 ways, for example, as 14371681 + 123210000 = 3791^2 + 11100^2 .

It is a cyclic number.

It is not a de Polignac number, because 137581681 - 2³ = 137581673 is a prime.

It is a super-2 number, since 2×137581681² = 37857437893571522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (137581601) 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, 608656 + ... + 608881.

It is an arithmetic number, because the mean of its divisors is an integer number (34699833).

Almost surely, 2^137581681 is an apocalyptic number.

It is an amenable number.

137581681 is a deficient number, since it is larger than the sum of its proper divisors (1217651).

137581681 is a wasteful number, since it uses less digits than its factorization.

137581681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1217650.

The product of its digits is 40320, while the sum is 40.

The square root of 137581681 is about 11729.5217720076. The cubic root of 137581681 is about 516.2422407361.

The spelling of 137581681 in words is "one hundred thirty-seven million, five hundred eighty-one thousand, six hundred eighty-one".