1808042421 has 4 divisors (see below), whose sum is σ = 2410723232. Its totient is φ = 1205361612.

The previous prime is 1808042399. The next prime is 1808042471. The reversal of 1808042421 is 1242408081.

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 1808042421 - 2¹⁰ = 1808041397 is a prime.

It is a super-2 number, since 2×1808042421² = 6538034792271082482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1808042471) 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, 301340401 + ... + 301340406.

It is an arithmetic number, because the mean of its divisors is an integer number (602680808).

Almost surely, 2^1808042421 is an apocalyptic number.

It is an amenable number.

1808042421 is a deficient number, since it is larger than the sum of its proper divisors (602680811).

1808042421 is an equidigital number, since it uses as much as digits as its factorization.

1808042421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 602680810.

The product of its (nonzero) digits is 4096, while the sum is 30.

The square root of 1808042421 is about 42521.0820770121. The cubic root of 1808042421 is about 1218.2493975401.

The spelling of 1808042421 in words is "one billion, eight hundred eight million, forty-two thousand, four hundred twenty-one".