19865813481 has 12 divisors (see below), whose sum is σ = 28749937008. Its totient is φ = 13218549624.

The previous prime is 19865813399. The next prime is 19865813507. The reversal of 19865813481 is 18431856891.

It is a happy number.

19865813481 is a `hidden beast` number, since 1 + 9 + 86 + 5 + 81 + 3 + 481 = 666.

It is not a de Polignac number, because 19865813481 - 2¹⁸ = 19865551337 is a prime.

It is a super-2 number, since 2×19865813481² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19865812481) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2105535 + ... + 2114948.

It is an arithmetic number, because the mean of its divisors is an integer number (2395828084).

Almost surely, 2^19865813481 is an apocalyptic number.

It is an amenable number.

19865813481 is a deficient number, since it is larger than the sum of its proper divisors (8884123527).

19865813481 is a wasteful number, since it uses less digits than its factorization.

19865813481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4221012 (or 4221009 counting only the distinct ones).

The product of its digits is 1658880, while the sum is 54.

The spelling of 19865813481 in words is "nineteen billion, eight hundred sixty-five million, eight hundred thirteen thousand, four hundred eighty-one".