19621491109 has 4 divisors (see below), whose sum is σ = 21405263040. Its totient is φ = 17837719180.

The previous prime is 19621491091. The next prime is 19621491133. The reversal of 19621491109 is 90119412691.

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 19621491109 - 2¹⁵ = 19621458341 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19621491209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 891885949 + ... + 891885970.

It is an arithmetic number, because the mean of its divisors is an integer number (5351315760).

Almost surely, 2^19621491109 is an apocalyptic number.

It is an amenable number.

19621491109 is a deficient number, since it is larger than the sum of its proper divisors (1783771931).

19621491109 is a wasteful number, since it uses less digits than its factorization.

19621491109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1783771930.

The product of its (nonzero) digits is 34992, while the sum is 43.

The spelling of 19621491109 in words is "nineteen billion, six hundred twenty-one million, four hundred ninety-one thousand, one hundred nine".