2121731 has 4 divisors (see below), whose sum is σ = 2124864. Its totient is φ = 2118600.

The previous prime is 2121683. The next prime is 2121737. The reversal of 2121731 is 1371212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2121731 - 2⁶ = 2121667 is a prime.

It is a super-2 number, since 2×2121731² = 9003484872722, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80 + ... + 2061.

It is an arithmetic number, because the mean of its divisors is an integer number (531216).

2^2121731 is an apocalyptic number.

2121731 is a deficient number, since it is larger than the sum of its proper divisors (3133).

2121731 is an equidigital number, since it uses as much as digits as its factorization.

2121731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3132.

The product of its digits is 84, while the sum is 17.

The square root of 2121731 is about 1456.6162844071. The cubic root of 2121731 is about 128.4981200551.

Adding to 2121731 its reverse (1371212), we get a palindrome (3492943).

The spelling of 2121731 in words is "two million, one hundred twenty-one thousand, seven hundred thirty-one".