19621170691 has 4 divisors (see below), whose sum is σ = 19684261584. Its totient is φ = 19558079800.

The previous prime is 19621170683. The next prime is 19621170703. The reversal of 19621170691 is 19607112691.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19607112691 = 67 ⋅292643473.

It is a cyclic number.

It is not a de Polignac number, because 19621170691 - 2³ = 19621170683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19621170601) 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, 31544980 + ... + 31545601.

It is an arithmetic number, because the mean of its divisors is an integer number (4921065396).

Almost surely, 2^19621170691 is an apocalyptic number.

19621170691 is a deficient number, since it is larger than the sum of its proper divisors (63090893).

19621170691 is an equidigital number, since it uses as much as digits as its factorization.

19621170691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63090892.

The product of its (nonzero) digits is 40824, while the sum is 43.

The spelling of 19621170691 in words is "nineteen billion, six hundred twenty-one million, one hundred seventy thousand, six hundred ninety-one".