1121991431 has 4 divisors (see below), whose sum is σ = 1223990664. Its totient is φ = 1019992200.

The previous prime is 1121991419. The next prime is 1121991433. The reversal of 1121991431 is 1341991211.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1121991431 is a prime.

It is a super-2 number, since 2×1121991431² = 2517729542474855522, 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 (1121991433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50999600 + ... + 50999621.

It is an arithmetic number, because the mean of its divisors is an integer number (305997666).

Almost surely, 2^1121991431 is an apocalyptic number.

1121991431 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1121991431 is a deficient number, since it is larger than the sum of its proper divisors (101999233).

1121991431 is a wasteful number, since it uses less digits than its factorization.

1121991431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101999232.

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

The square root of 1121991431 is about 33496.1405388740. The cubic root of 1121991431 is about 1039.1139615062.

The spelling of 1121991431 in words is "one billion, one hundred twenty-one million, nine hundred ninety-one thousand, four hundred thirty-one".