919191918191 has 4 divisors (see below), whose sum is σ = 940568474472. Its totient is φ = 897815361912.

The previous prime is 919191918163. The next prime is 919191918193. The reversal of 919191918191 is 191819191919.

919191918191 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 191819191919 = 137 ⋅1400140087.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-919191918191 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 919191918191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (919191918193) 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, 10688278076 + ... + 10688278161.

It is an arithmetic number, because the mean of its divisors is an integer number (235142118618).

Almost surely, 2^919191918191 is an apocalyptic number.

919191918191 is a deficient number, since it is larger than the sum of its proper divisors (21376556281).

919191918191 is a wasteful number, since it uses less digits than its factorization.

919191918191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21376556280.

The product of its digits is 472392, while the sum is 59.

The spelling of 919191918191 in words is "nine hundred nineteen billion, one hundred ninety-one million, nine hundred eighteen thousand, one hundred ninety-one".