919191919191919 has 4 divisors (see below), whose sum is σ = 919192741170496. Its totient is φ = 919191097213344.

The previous prime is 919191919191899. The next prime is 919191919191961.

It is a happy number.

919191919191919 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-919191919191919 is a prime.

It is a super-2 number, since 2×919191919191919² (a number of 31 digits) contains 22 as substring.

It is a Duffinian number.

919191919191919 is an undulating number in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (919191919191019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 409309599 + ... + 411549184.

It is an arithmetic number, because the mean of its divisors is an integer number (229798185292624).

Almost surely, 2^{919191919191919} is an apocalyptic number.

919191919191919 is a deficient number, since it is larger than the sum of its proper divisors (821978577).

919191919191919 is a wasteful number, since it uses less digits than its factorization.

919191919191919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 821978576.

The product of its digits is 43046721, while the sum is 79.

It can be divided in two parts, 9 and 19191919191919, that multiplied together give a palindrome (172727272727271).

The spelling of 919191919191919 in words is "nine hundred nineteen trillion, one hundred ninety-one billion, nine hundred nineteen million, one hundred ninety-one thousand, nine hundred nineteen".