19698121 has 4 divisors (see below), whose sum is σ = 20856852. Its totient is φ = 18539392.

The previous prime is 19698109. The next prime is 19698127. The reversal of 19698121 is 12189691.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12189691 = 61 ⋅199831.

It can be written as a sum of positive squares in 2 ways, for example, as 6996025 + 12702096 = 2645^2 + 3564^2 .

It is a cyclic number.

It is not a de Polignac number, because 19698121 - 2¹⁵ = 19665353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19698127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 579340 + ... + 579373.

It is an arithmetic number, because the mean of its divisors is an integer number (5214213).

Almost surely, 2^19698121 is an apocalyptic number.

It is an amenable number.

19698121 is a deficient number, since it is larger than the sum of its proper divisors (1158731).

19698121 is a wasteful number, since it uses less digits than its factorization.

19698121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1158730.

The product of its digits is 7776, while the sum is 37.

The square root of 19698121 is about 4438.2565270610. The cubic root of 19698121 is about 270.0691226773.

The spelling of 19698121 in words is "nineteen million, six hundred ninety-eight thousand, one hundred twenty-one".