1840421 has 4 divisors (see below), whose sum is σ = 2007744. Its totient is φ = 1673100.

The previous prime is 1840393. The next prime is 1840429. The reversal of 1840421 is 1240481.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1240481 = 11 ⋅112771.

It is not a de Polignac number, because 1840421 - 2¹⁴ = 1824037 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1840393 and 1840402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1840429) 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, 83645 + ... + 83666.

It is an arithmetic number, because the mean of its divisors is an integer number (501936).

2^1840421 is an apocalyptic number.

1840421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1840421 is a deficient number, since it is larger than the sum of its proper divisors (167323).

1840421 is a wasteful number, since it uses less digits than its factorization.

1840421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167322.

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 1840421 is about 1356.6211704083. The cubic root of 1840421 is about 122.5478585734.

The spelling of 1840421 in words is "one million, eight hundred forty thousand, four hundred twenty-one".