137721 has 8 divisors (see below), whose sum is σ = 190080. Its totient is φ = 88592.

The previous prime is 137713. The next prime is 137723. The reversal of 137721 is 127731.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 137721 - 2³ = 137713 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 137721.

It is not an unprimeable number, because it can be changed into a prime (137723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 705 + ... + 878.

It is an arithmetic number, because the mean of its divisors is an integer number (23760).

2¹³⁷⁷²¹ is an apocalyptic number.

It is an amenable number.

137721 is a deficient number, since it is larger than the sum of its proper divisors (52359).

137721 is a wasteful number, since it uses less digits than its factorization.

137721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1615.

The product of its digits is 294, while the sum is 21.

The square root of 137721 is about 371.1078010498. The cubic root of 137721 is about 51.6416435656.

It can be divided in two parts, 137 and 721, that added together give a palindrome (858).

The spelling of 137721 in words is "one hundred thirty-seven thousand, seven hundred twenty-one".