19018421501 has 4 divisors (see below), whose sum is σ = 19018703004. Its totient is φ = 19018140000.

The previous prime is 19018421483. The next prime is 19018421533. The reversal of 19018421501 is 10512481091.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 10512481091 = 7 ⋅1501783013.

It can be written as a sum of positive squares in 2 ways, for example, as 14215792900 + 4802628601 = 119230^2 + 69301^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19018421501 is a prime.

It is a deceptive number, since it divides R_19018421500.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19018421701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28151 + ... + 197051.

It is an arithmetic number, because the mean of its divisors is an integer number (4754675751).

Almost surely, 2^19018421501 is an apocalyptic number.

19018421501 is the 112601-st pentagonal number.

It is an amenable number.

19018421501 is a deficient number, since it is larger than the sum of its proper divisors (281503).

19018421501 is a wasteful number, since it uses less digits than its factorization.

19018421501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 281502.

The product of its (nonzero) digits is 2880, while the sum is 32.

The spelling of 19018421501 in words is "nineteen billion, eighteen million, four hundred twenty-one thousand, five hundred one".