19805969 has 4 divisors (see below), whose sum is σ = 20971044. Its totient is φ = 18640896.

The previous prime is 19805959. The next prime is 19805983. The reversal of 19805969 is 96950891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96950891 = 4093 ⋅23687.

It can be written as a sum of positive squares in 2 ways, for example, as 6027025 + 13778944 = 2455^2 + 3712^2 .

It is a cyclic number.

It is not a de Polignac number, because 19805969 - 2⁸ = 19805713 is a prime.

It is a super-2 number, since 2×19805969² = 784552816057922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19805909) 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, 582512 + ... + 582545.

It is an arithmetic number, because the mean of its divisors is an integer number (5242761).

Almost surely, 2^19805969 is an apocalyptic number.

It is an amenable number.

19805969 is a deficient number, since it is larger than the sum of its proper divisors (1165075).

19805969 is a wasteful number, since it uses less digits than its factorization.

19805969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1165074.

The product of its (nonzero) digits is 174960, while the sum is 47.

The square root of 19805969 is about 4450.3897582122. The cubic root of 19805969 is about 270.5611056393.

The spelling of 19805969 in words is "nineteen million, eight hundred five thousand, nine hundred sixty-nine".