19804156369 has 4 divisors (see below), whose sum is σ = 19857250996. Its totient is φ = 19751061744.

The previous prime is 19804156321. The next prime is 19804156387. The reversal of 19804156369 is 96365140891.

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 14856440769 + 4947715600 = 121887^2 + 70340^2 .

It is a cyclic number.

It is not a de Polignac number, because 19804156369 - 2¹⁹ = 19803632081 is a prime.

It is a super-2 number, since 2×19804156369² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19804150369) 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, 26546754 + ... + 26547499.

It is an arithmetic number, because the mean of its divisors is an integer number (4964312749).

Almost surely, 2^19804156369 is an apocalyptic number.

It is an amenable number.

19804156369 is a deficient number, since it is larger than the sum of its proper divisors (53094627).

19804156369 is an equidigital number, since it uses as much as digits as its factorization.

19804156369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53094626.

The product of its (nonzero) digits is 1399680, while the sum is 52.

The spelling of 19804156369 in words is "nineteen billion, eight hundred four million, one hundred fifty-six thousand, three hundred sixty-nine".