2126721 has 4 divisors (see below), whose sum is σ = 2835632. Its totient is φ = 1417812.

The previous prime is 2126687. The next prime is 2126749. The reversal of 2126721 is 1276212.

2126721 is nontrivially palindromic in base 2.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 2126721 - 2¹⁴ = 2110337 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2126771) 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, 354451 + ... + 354456.

It is an arithmetic number, because the mean of its divisors is an integer number (708908).

2^2126721 is an apocalyptic number.

It is an amenable number.

2126721 is a deficient number, since it is larger than the sum of its proper divisors (708911).

2126721 is an equidigital number, since it uses as much as digits as its factorization.

2126721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708910.

The product of its digits is 336, while the sum is 21.

The square root of 2126721 is about 1458.3281523717. The cubic root of 2126721 is about 128.5987774273.

The spelling of 2126721 in words is "two million, one hundred twenty-six thousand, seven hundred twenty-one".