19989395405 has 24 divisors (see below), whose sum is σ = 27920476440. Its totient is φ = 13698706560.

The previous prime is 19989395401. The next prime is 19989395443. The reversal of 19989395405 is 50459398991.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1094418724 + 18894976681 = 33082^2 + 137459^2 .

It is not a de Polignac number, because 19989395405 - 2² = 19989395401 is a prime.

It is a super-2 number, since 2×19989395405² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19989395401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 394835 + ... + 442575.

It is an arithmetic number, because the mean of its divisors is an integer number (1163353185).

Almost surely, 2^19989395405 is an apocalyptic number.

It is an amenable number.

19989395405 is a deficient number, since it is larger than the sum of its proper divisors (7931081035).

19989395405 is a wasteful number, since it uses less digits than its factorization.

19989395405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49469 (or 49462 counting only the distinct ones).

The product of its (nonzero) digits is 15746400, while the sum is 62.

The spelling of 19989395405 in words is "nineteen billion, nine hundred eighty-nine million, three hundred ninety-five thousand, four hundred five".