2090721 has 4 divisors (see below), whose sum is σ = 2787632. Its totient is φ = 1393812.

The previous prime is 2090719. The next prime is 2090749. The reversal of 2090721 is 1270902.

It is a happy number.

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 2090721 - 2¹ = 2090719 is a prime.

It is a super-2 number, since 2×2090721² = 8742228599682, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

2090721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2090771) 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, 348451 + ... + 348456.

It is an arithmetic number, because the mean of its divisors is an integer number (696908).

2^2090721 is an apocalyptic number.

It is an amenable number.

2090721 is a deficient number, since it is larger than the sum of its proper divisors (696911).

2090721 is an equidigital number, since it uses as much as digits as its factorization.

2090721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 696910.

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 2090721 is about 1445.9325710420. The cubic root of 2090721 is about 127.8690270007.

The spelling of 2090721 in words is "two million, ninety thousand, seven hundred twenty-one".