1691971919 has 6 divisors (see below), whose sum is σ = 1859770920. Its totient is φ = 1538156180.

The previous prime is 1691971889. The next prime is 1691971973. The reversal of 1691971919 is 9191791961.

It is not a de Polignac number, because 1691971919 - 2¹⁶ = 1691906383 is a prime.

It is a super-2 number, since 2×1691971919² = 5725537949369085122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1691971979) by changing a digit.

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

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6991499 + ... + 6991740.

It is an arithmetic number, because the mean of its divisors is an integer number (309961820).

Almost surely, 2^1691971919 is an apocalyptic number.

1691971919 is a deficient number, since it is larger than the sum of its proper divisors (167799001).

1691971919 is a wasteful number, since it uses less digits than its factorization.

1691971919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13983261 (or 13983250 counting only the distinct ones).

The product of its digits is 275562, while the sum is 53.

The square root of 1691971919 is about 41133.5862647545. The cubic root of 1691971919 is about 1191.6015249072.

The spelling of 1691971919 in words is "one billion, six hundred ninety-one million, nine hundred seventy-one thousand, nine hundred nineteen".