19889634557 has 4 divisors (see below), whose sum is σ = 21419606460. Its totient is φ = 18359662656.

The previous prime is 19889634547. The next prime is 19889634559. The reversal of 19889634557 is 75543698891.

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 3057426436 + 16832208121 = 55294^2 + 129739^2 .

It is a cyclic number.

It is not a de Polignac number, because 19889634557 - 2¹² = 19889630461 is a prime.

It is a super-2 number, since 2×19889634557² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19889634493 and 19889634502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19889634559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 764985932 + ... + 764985957.

It is an arithmetic number, because the mean of its divisors is an integer number (5354901615).

Almost surely, 2^19889634557 is an apocalyptic number.

It is an amenable number.

19889634557 is a deficient number, since it is larger than the sum of its proper divisors (1529971903).

19889634557 is a wasteful number, since it uses less digits than its factorization.

19889634557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1529971902.

The product of its digits is 65318400, while the sum is 65.

The spelling of 19889634557 in words is "nineteen billion, eight hundred eighty-nine million, six hundred thirty-four thousand, five hundred fifty-seven".