19666872413 has 4 divisors (see below), whose sum is σ = 19943870688. Its totient is φ = 19389874140.

The previous prime is 19666872397. The next prime is 19666872443. The reversal of 19666872413 is 31427866691.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31427866691 = 13 ⋅2417528207.

It is a cyclic number.

It is not a de Polignac number, because 19666872413 - 2⁴ = 19666872397 is a prime.

It is a super-3 number, since 3×19666872413³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19666872443) 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, 138499031 + ... + 138499172.

It is an arithmetic number, because the mean of its divisors is an integer number (4985967672).

Almost surely, 2^19666872413 is an apocalyptic number.

It is an amenable number.

19666872413 is a deficient number, since it is larger than the sum of its proper divisors (276998275).

19666872413 is an equidigital number, since it uses as much as digits as its factorization.

19666872413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276998274.

The product of its digits is 2612736, while the sum is 53.

The spelling of 19666872413 in words is "nineteen billion, six hundred sixty-six million, eight hundred seventy-two thousand, four hundred thirteen".