1820251 has 4 divisors (see below), whose sum is σ = 1830600. Its totient is φ = 1809904.

The previous prime is 1820249. The next prime is 1820261. The reversal of 1820251 is 1520281.

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 1820251 - 2¹ = 1820249 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 (1820201) 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, 4906 + ... + 5263.

It is an arithmetic number, because the mean of its divisors is an integer number (457650).

2^1820251 is an apocalyptic number.

1820251 is a deficient number, since it is larger than the sum of its proper divisors (10349).

1820251 is a wasteful number, since it uses less digits than its factorization.

1820251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10348.

The product of its (nonzero) digits is 160, while the sum is 19.

The square root of 1820251 is about 1349.1667799053. The cubic root of 1820251 is about 122.0985274130.

The spelling of 1820251 in words is "one million, eight hundred twenty thousand, two hundred fifty-one".