10991831 has 2 divisors, whose sum is σ = 10991832. Its totient is φ = 10991830.

The previous prime is 10991807. The next prime is 10991833. The reversal of 10991831 is 13819901.

It is a strong prime.

It is an emirp because it is prime and its reverse (13819901) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 10991831 - 2¹⁸ = 10729687 is a prime.

It is a super-2 number, since 2×10991831² = 241640697465122, which contains 22 as substring.

Together with 10991833, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (10991833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5495915 + 5495916.

It is an arithmetic number, because the mean of its divisors is an integer number (5495916).

Almost surely, 2^10991831 is an apocalyptic number.

10991831 is a deficient number, since it is larger than the sum of its proper divisors (1).

10991831 is an equidigital number, since it uses as much as digits as its factorization.

10991831 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 32.

The square root of 10991831 is about 3315.3930385401. The cubic root of 10991831 is about 222.3429418068.

The spelling of 10991831 in words is "ten million, nine hundred ninety-one thousand, eight hundred thirty-one".