1691239331 has 4 divisors (see below), whose sum is σ = 1691386032. Its totient is φ = 1691092632.

The previous prime is 1691239279. The next prime is 1691239337. The reversal of 1691239331 is 1339321961.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1339321961 = 2657 ⋅504073.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1691239331 is a prime.

It is a super-2 number, since 2×1691239331² = 5720580949442655122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1691239337) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 54431 + ... + 79656.

It is an arithmetic number, because the mean of its divisors is an integer number (422846508).

Almost surely, 2^1691239331 is an apocalyptic number.

1691239331 is a deficient number, since it is larger than the sum of its proper divisors (146701).

1691239331 is a wasteful number, since it uses less digits than its factorization.

1691239331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146700.

The product of its digits is 26244, while the sum is 38.

The square root of 1691239331 is about 41124.6803148669. The cubic root of 1691239331 is about 1191.4295206739.

The spelling of 1691239331 in words is "one billion, six hundred ninety-one million, two hundred thirty-nine thousand, three hundred thirty-one".