1805745421 has 2 divisors, whose sum is σ = 1805745422. Its totient is φ = 1805745420.

The previous prime is 1805745419. The next prime is 1805745437. The reversal of 1805745421 is 1245475081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1746069796 + 59675625 = 41786^2 + 7725^2 .

It is a cyclic number.

It is not a de Polignac number, because 1805745421 - 2¹ = 1805745419 is a prime.

Together with 1805745419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1805745401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 902872710 + 902872711.

It is an arithmetic number, because the mean of its divisors is an integer number (902872711).

Almost surely, 2^1805745421 is an apocalyptic number.

It is an amenable number.

1805745421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1805745421 is an equidigital number, since it uses as much as digits as its factorization.

1805745421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 44800, while the sum is 37.

The square root of 1805745421 is about 42494.0633618391. The cubic root of 1805745421 is about 1217.7332767718.

The spelling of 1805745421 in words is "one billion, eight hundred five million, seven hundred forty-five thousand, four hundred twenty-one".