1898921 has 2 divisors, whose sum is σ = 1898922. Its totient is φ = 1898920.

The previous prime is 1898893. The next prime is 1898959. The reversal of 1898921 is 1298981.

It is an a-pointer prime, because the next prime (1898959) can be obtained adding 1898921 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1357225 + 541696 = 1165^2 + 736^2 .

It is an emirp because it is prime and its reverse (1298981) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1898921 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a plaindrome in base 15.

It is not a weakly prime, because it can be changed into another prime (1898521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 949460 + 949461.

It is an arithmetic number, because the mean of its divisors is an integer number (949461).

2^1898921 is an apocalyptic number.

It is an amenable number.

1898921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1898921 is an equidigital number, since it uses as much as digits as its factorization.

1898921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 38.

The square root of 1898921 is about 1378.0134251886. The cubic root of 1898921 is about 123.8327827558.

The spelling of 1898921 in words is "one million, eight hundred ninety-eight thousand, nine hundred twenty-one".