137781 has 20 divisors (see below), whose sum is σ = 236192. Its totient is φ = 78732.

The previous prime is 137777. The next prime is 137791. The reversal of 137781 is 187731.

It is not a de Polignac number, because 137781 - 2^{2} = 137777 is a prime.

It is a super-2 number, since 2×137781^{2} = 37967207922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a plaindrome in base 12.

It is a nialpdrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (137771) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 19680 + ... + 19686.

137781 is a Friedman number, since it can be written as 3^8*(7+7*(1+1)), using all its digits and the basic arithmetic operations.

2^{137781} is an apocalyptic number.

It is an amenable number.

137781 is a deficient number, since it is larger than the sum of its proper divisors (98411).

137781 is an frugal number, since it uses more digits than its factorization.

137781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34 (or 10 counting only the distinct ones).

The product of its digits is 1176, while the sum is 27.

The square root of 137781 is about 371.1886312914. The cubic root of 137781 is about 51.6491419349.

The spelling of 137781 in words is "one hundred thirty-seven thousand, seven hundred eighty-one".

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