2071821 has 4 divisors (see below), whose sum is σ = 2762432. Its totient is φ = 1381212.

The previous prime is 2071819. The next prime is 2071837. The reversal of 2071821 is 1281702.

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 2071821 - 2¹ = 2071819 is a prime.

It is a D-number.

It is a Duffinian number.

2071821 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2071801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 345301 + ... + 345306.

It is an arithmetic number, because the mean of its divisors is an integer number (690608).

2^2071821 is an apocalyptic number.

It is an amenable number.

2071821 is a deficient number, since it is larger than the sum of its proper divisors (690611).

2071821 is an equidigital number, since it uses as much as digits as its factorization.

2071821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 690610.

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 2071821 is about 1439.3821591224. The cubic root of 2071821 is about 127.4825504763.

The spelling of 2071821 in words is "two million, seventy-one thousand, eight hundred twenty-one".