1691321191 has 18 divisors (see below), whose sum is σ = 1995378480. Its totient is φ = 1429187760.

The previous prime is 1691321183. The next prime is 1691321221. The reversal of 1691321191 is 1911231961.

It is not a de Polignac number, because 1691321191 - 2³ = 1691321183 is a prime.

It is a super-2 number, since 2×1691321191² = 5721134742251316962, 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 (1691321161) 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 17 ways as a sum of consecutive naturals, for example, 2558401 + ... + 2559061.

It is an arithmetic number, because the mean of its divisors is an integer number (110854360).

Almost surely, 2^1691321191 is an apocalyptic number.

1691321191 is a deficient number, since it is larger than the sum of its proper divisors (304057289).

1691321191 is an frugal number, since it uses more digits than its factorization.

1691321191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1415 (or 747 counting only the distinct ones).

The product of its digits is 2916, while the sum is 34.

The square root of 1691321191 is about 41125.6755689192. The cubic root of 1691321191 is about 1191.4487430365.

The spelling of 1691321191 in words is "one billion, six hundred ninety-one million, three hundred twenty-one thousand, one hundred ninety-one".