19887049361 has 4 divisors (see below), whose sum is σ = 21056875812. Its totient is φ = 18717222912.

The previous prime is 19887049349. The next prime is 19887049433. The reversal of 19887049361 is 16394078891.

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 7800245761 + 12086803600 = 88319^2 + 109940^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19887049361 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19887049297 and 19887049306.

It is not an unprimeable number, because it can be changed into a prime (19887049961) 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, 584913200 + ... + 584913233.

It is an arithmetic number, because the mean of its divisors is an integer number (5264218953).

Almost surely, 2^19887049361 is an apocalyptic number.

It is an amenable number.

19887049361 is a deficient number, since it is larger than the sum of its proper divisors (1169826451).

19887049361 is a wasteful number, since it uses less digits than its factorization.

19887049361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1169826450.

The product of its (nonzero) digits is 2612736, while the sum is 56.

The spelling of 19887049361 in words is "nineteen billion, eight hundred eighty-seven million, forty-nine thousand, three hundred sixty-one".