1802021 has 4 divisors (see below), whose sum is σ = 1940652. Its totient is φ = 1663392.

The previous prime is 1801997. The next prime is 1802029. The reversal of 1802021 is 1202081.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 722500 + 1079521 = 850^2 + 1039^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1802021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1801987 and 1802005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1802029) 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, 69296 + ... + 69321.

It is an arithmetic number, because the mean of its divisors is an integer number (485163).

2^1802021 is an apocalyptic number.

It is an amenable number.

1802021 is a deficient number, since it is larger than the sum of its proper divisors (138631).

1802021 is a wasteful number, since it uses less digits than its factorization.

1802021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138630.

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 1802021 is about 1342.3937574348. The cubic root of 1802021 is about 121.6895492917.

The spelling of 1802021 in words is "one million, eight hundred two thousand, twenty-one".