19660821603 has 4 divisors (see below), whose sum is σ = 26214428808. Its totient is φ = 13107214400.

The previous prime is 19660821601. The next prime is 19660821617. The reversal of 19660821603 is 30612806691.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19660821603 - 2¹ = 19660821601 is a prime.

It is a super-2 number, since 2×19660821603² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19660821601) 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, 3276803598 + ... + 3276803603.

It is an arithmetic number, because the mean of its divisors is an integer number (6553607202).

Almost surely, 2^19660821603 is an apocalyptic number.

19660821603 is a deficient number, since it is larger than the sum of its proper divisors (6553607205).

19660821603 is an equidigital number, since it uses as much as digits as its factorization.

19660821603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6553607204.

The product of its (nonzero) digits is 93312, while the sum is 42.

The spelling of 19660821603 in words is "nineteen billion, six hundred sixty million, eight hundred twenty-one thousand, six hundred three".