1991869233 has 4 divisors (see below), whose sum is σ = 2655825648. Its totient is φ = 1327912820.

The previous prime is 1991869223. The next prime is 1991869247. The reversal of 1991869233 is 3329681991.

It is a happy number.

1991869233 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1991869233 - 2⁶ = 1991869169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1991869213) 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, 331978203 + ... + 331978208.

It is an arithmetic number, because the mean of its divisors is an integer number (663956412).

Almost surely, 2^1991869233 is an apocalyptic number.

It is an amenable number.

1991869233 is a deficient number, since it is larger than the sum of its proper divisors (663956415).

1991869233 is an equidigital number, since it uses as much as digits as its factorization.

1991869233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663956414.

The product of its digits is 629856, while the sum is 51.

The square root of 1991869233 is about 44630.3622324534. The cubic root of 1991869233 is about 1258.2113768896.

The spelling of 1991869233 in words is "one billion, nine hundred ninety-one million, eight hundred sixty-nine thousand, two hundred thirty-three".