1899421 has 2 divisors, whose sum is σ = 1899422. Its totient is φ = 1899420.

The previous prime is 1899419. The next prime is 1899437. The reversal of 1899421 is 1249981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1276900 + 622521 = 1130^2 + 789^2 .

It is a cyclic number.

It is not a de Polignac number, because 1899421 - 2¹ = 1899419 is a prime.

Together with 1899419, it forms a pair of twin primes.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1899481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 949710 + 949711.

It is an arithmetic number, because the mean of its divisors is an integer number (949711).

2^1899421 is an apocalyptic number.

It is an amenable number.

1899421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1899421 is an equidigital number, since it uses as much as digits as its factorization.

1899421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 34.

The square root of 1899421 is about 1378.1948338316. The cubic root of 1899421 is about 123.8436504990.

The spelling of 1899421 in words is "one million, eight hundred ninety-nine thousand, four hundred twenty-one".