19390121 has 4 divisors (see below), whose sum is σ = 19432644. Its totient is φ = 19347600.

The previous prime is 19390099. The next prime is 19390123. The reversal of 19390121 is 12109391.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14707225 + 4682896 = 3835^2 + 2164^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19390121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19390123) 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, 20570 + ... + 21491.

It is an arithmetic number, because the mean of its divisors is an integer number (4858161).

Almost surely, 2^19390121 is an apocalyptic number.

It is an amenable number.

19390121 is a deficient number, since it is larger than the sum of its proper divisors (42523).

19390121 is an equidigital number, since it uses as much as digits as its factorization.

19390121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42522.

The product of its (nonzero) digits is 486, while the sum is 26.

The square root of 19390121 is about 4403.4215105983. The cubic root of 19390121 is about 268.6541207648.

The spelling of 19390121 in words is "nineteen million, three hundred ninety thousand, one hundred twenty-one".