121731 has 4 divisors (see below), whose sum is σ = 162312. Its totient is φ = 81152.

The previous prime is 121727. The next prime is 121763. The reversal of 121731 is 137121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 137121 = 3 ⋅45707.

It is a cyclic number.

It is not a de Polignac number, because 121731 - 2² = 121727 is a prime.

It is a super-2 number, since 2×121731² = 29636872722, which contains 22 as substring.

It is an Ulam number.

It is a D-number.

121731 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 121731.

It is not an unprimeable number, because it can be changed into a prime (121711) 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, 20286 + ... + 20291.

It is an arithmetic number, because the mean of its divisors is an integer number (40578).

2¹²¹⁷³¹ is an apocalyptic number.

121731 is a deficient number, since it is larger than the sum of its proper divisors (40581).

121731 is an equidigital number, since it uses as much as digits as its factorization.

121731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40580.

The product of its digits is 42, while the sum is 15.

The square root of 121731 is about 348.8996990540. The cubic root of 121731 is about 49.5602775531.

Adding to 121731 its reverse (137121), we get a palindrome (258852).

The spelling of 121731 in words is "one hundred twenty-one thousand, seven hundred thirty-one".