19811620065 has 8 divisors (see below), whose sum is σ = 31698592128. Its totient is φ = 10566197360.

The previous prime is 19811620063. The next prime is 19811620069. The reversal of 19811620065 is 56002611891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 19811620065 - 2¹ = 19811620063 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19811620063) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 660387321 + ... + 660387350.

It is an arithmetic number, because the mean of its divisors is an integer number (3962324016).

Almost surely, 2^19811620065 is an apocalyptic number.

19811620065 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19811620065 is a deficient number, since it is larger than the sum of its proper divisors (11886972063).

19811620065 is a wasteful number, since it uses less digits than its factorization.

19811620065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1320774679.

The product of its (nonzero) digits is 25920, while the sum is 39.

The spelling of 19811620065 in words is "nineteen billion, eight hundred eleven million, six hundred twenty thousand, sixty-five".