2345821 has 4 divisors (see below), whose sum is σ = 2348892. Its totient is φ = 2342752.

The previous prime is 2345809. The next prime is 2345831. The reversal of 2345821 is 1285432.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 881721 + 1464100 = 939^2 + 1210^2 .

It is a cyclic number.

It is not a de Polignac number, because 2345821 - 2¹⁵ = 2313053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2345831) 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, 615 + ... + 2251.

It is an arithmetic number, because the mean of its divisors is an integer number (587223).

2^2345821 is an apocalyptic number.

It is an amenable number.

2345821 is a deficient number, since it is larger than the sum of its proper divisors (3071).

2345821 is a wasteful number, since it uses less digits than its factorization.

2345821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3070.

The product of its digits is 1920, while the sum is 25.

The square root of 2345821 is about 1531.6073256550. The cubic root of 2345821 is about 132.8714343566.

The spelling of 2345821 in words is "two million, three hundred forty-five thousand, eight hundred twenty-one".