19498820261 has 4 divisors (see below), whose sum is σ = 19829308800. Its totient is φ = 19168331724.

The previous prime is 19498820213. The next prime is 19498820269. The reversal of 19498820261 is 16202889491.

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, and also an emirpimes, since its reverse is a distinct semiprime: 16202889491 = 2689 ⋅6025619.

It is a cyclic number.

It is not a de Polignac number, because 19498820261 - 2³⁴ = 2318951077 is a prime.

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 (19498820269) 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, 165244181 + ... + 165244298.

It is an arithmetic number, because the mean of its divisors is an integer number (4957327200).

Almost surely, 2^19498820261 is an apocalyptic number.

It is an amenable number.

19498820261 is a deficient number, since it is larger than the sum of its proper divisors (330488539).

19498820261 is an equidigital number, since it uses as much as digits as its factorization.

19498820261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330488538.

The product of its (nonzero) digits is 497664, while the sum is 50.

The spelling of 19498820261 in words is "nineteen billion, four hundred ninety-eight million, eight hundred twenty thousand, two hundred sixty-one".