19638563401 has 4 divisors (see below), whose sum is σ = 19654754692. Its totient is φ = 19622372112.

The previous prime is 19638563393. The next prime is 19638563407. The reversal of 19638563401 is 10436583691.

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 1343295801 + 18295267600 = 36651^2 + 135260^2 .

It is a cyclic number.

It is not a de Polignac number, because 19638563401 - 2³ = 19638563393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19638563407) 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, 8093826 + ... + 8096251.

It is an arithmetic number, because the mean of its divisors is an integer number (4913688673).

Almost surely, 2^19638563401 is an apocalyptic number.

It is an amenable number.

19638563401 is a deficient number, since it is larger than the sum of its proper divisors (16191291).

19638563401 is a wasteful number, since it uses less digits than its factorization.

19638563401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16191290.

The product of its (nonzero) digits is 466560, while the sum is 46.

The spelling of 19638563401 in words is "nineteen billion, six hundred thirty-eight million, five hundred sixty-three thousand, four hundred one".