19807975949 has 4 divisors (see below), whose sum is σ = 19814403936. Its totient is φ = 19801547964.

The previous prime is 19807975939. The next prime is 19807975961. The reversal of 19807975949 is 94957970891.

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.

It is a cyclic number.

It is not a de Polignac number, because 19807975949 - 2²⁰ = 19806927373 is a prime.

It is a super-2 number, since 2×19807975949² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19807975909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3209369 + ... + 3215534.

It is an arithmetic number, because the mean of its divisors is an integer number (4953600984).

Almost surely, 2^19807975949 is an apocalyptic number.

It is an amenable number.

19807975949 is a deficient number, since it is larger than the sum of its proper divisors (6427987).

19807975949 is an equidigital number, since it uses as much as digits as its factorization.

19807975949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6427986.

The product of its (nonzero) digits is 51438240, while the sum is 68.

The spelling of 19807975949 in words is "nineteen billion, eight hundred seven million, nine hundred seventy-five thousand, nine hundred forty-nine".