1919191919 has 16 divisors (see below), whose sum is σ = 2077340160. Its totient is φ = 1767096000.

The previous prime is 1919191913. The next prime is 1919191969. The reversal of 1919191919 is 9191919191.

It is a cyclic number.

It is not a de Polignac number, because 1919191919 - 2⁴ = 1919191903 is a prime.

It is a super-2 number, since 2×1919191919² = 7366595243909805122, which contains 22 as substring.

It is a Duffinian number.

1919191919 is an undulating number in base 10.

1919191919 is a modest number, since divided by 191919 gives 1919 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1919191913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is an upside-down number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 206564 + ... + 215654.

It is an arithmetic number, because the mean of its divisors is an integer number (129833760).

Almost surely, 2^1919191919 is an apocalyptic number.

1919191919 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1919191919 is a deficient number, since it is larger than the sum of its proper divisors (158148241).

1919191919 is a wasteful number, since it uses less digits than its factorization.

1919191919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9422.

The product of its digits is 59049, while the sum is 50.

The square root of 1919191919 is about 43808.5827093276. The cubic root of 1919191919 is about 1242.7186101669.

The spelling of 1919191919 in words is "one billion, nine hundred nineteen million, one hundred ninety-one thousand, nine hundred nineteen".