19961139769 has 4 divisors (see below), whose sum is σ = 20095107300. Its totient is φ = 19827172240.

The previous prime is 19961139701. The next prime is 19961139773. The reversal of 19961139769 is 96793116991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96793116991 = 79 ⋅1225229329.

It can be written as a sum of positive squares in 2 ways, for example, as 2679408169 + 17281731600 = 51763^2 + 131460^2 .

It is a cyclic number.

It is not a de Polignac number, because 19961139769 - 2²¹ = 19959042617 is a prime.

It is a super-2 number, since 2×19961139769² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19961139799) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66983542 + ... + 66983839.

It is an arithmetic number, because the mean of its divisors is an integer number (5023776825).

Almost surely, 2^19961139769 is an apocalyptic number.

It is an amenable number.

19961139769 is a deficient number, since it is larger than the sum of its proper divisors (133967531).

19961139769 is a wasteful number, since it uses less digits than its factorization.

19961139769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133967530.

The product of its digits is 4960116, while the sum is 61.

The spelling of 19961139769 in words is "nineteen billion, nine hundred sixty-one million, one hundred thirty-nine thousand, seven hundred sixty-nine".