18898421 has 2 divisors, whose sum is σ = 18898422. Its totient is φ = 18898420.

The previous prime is 18898409. The next prime is 18898423. The reversal of 18898421 is 12489881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15888196 + 3010225 = 3986^2 + 1735^2 .

It is a cyclic number.

It is not a de Polignac number, because 18898421 - 2¹⁴ = 18882037 is a prime.

Together with 18898423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18898423) 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, 9449210 + 9449211.

It is an arithmetic number, because the mean of its divisors is an integer number (9449211).

Almost surely, 2^18898421 is an apocalyptic number.

It is an amenable number.

18898421 is a deficient number, since it is larger than the sum of its proper divisors (1).

18898421 is an equidigital number, since it uses as much as digits as its factorization.

18898421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36864, while the sum is 41.

The square root of 18898421 is about 4347.2314178107. The cubic root of 18898421 is about 266.3637823246.

The spelling of 18898421 in words is "eighteen million, eight hundred ninety-eight thousand, four hundred twenty-one".