191919191919 has 128 divisors (see below), whose sum is σ = 343886161920. Its totient is φ = 92378880000.

The previous prime is 191919191899. The next prime is 191919191953. The reversal of 191919191919 is 919191919191.

It is not a de Polignac number, because 191919191919 - 2³⁶ = 123199715183 is a prime.

It is a super-2 number, since 2×191919191919² (a number of 23 digits) contains 22 as substring.

191919191919 is an undulating number in base 10.

191919191919 is a modest number, since divided by 19191919 gives 1919 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191919193919) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 19378869 + ... + 19388769.

It is an arithmetic number, because the mean of its divisors is an integer number (2686610640).

Almost surely, 2^191919191919 is an apocalyptic number.

191919191919 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

191919191919 is a deficient number, since it is larger than the sum of its proper divisors (151966970001).

191919191919 is a wasteful number, since it uses less digits than its factorization.

191919191919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10081.

The product of its digits is 531441, while the sum is 60.

The spelling of 191919191919 in words is "one hundred ninety-one billion, nine hundred nineteen million, one hundred ninety-one thousand, nine hundred nineteen".