2231001991 has 2 divisors, whose sum is σ = 2231001992. Its totient is φ = 2231001990.

The previous prime is 2231001977. The next prime is 2231002019. The reversal of 2231001991 is 1991001322.

2231001991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an a-pointer prime, because the next prime (2231002019) can be obtained adding 2231001991 to its sum of digits (28).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2231001991 - 2¹¹ = 2230999943 is a prime.

It is a super-3 number, since 3×2231001991³ (a number of 29 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2231001901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1115500995 + 1115500996.

It is an arithmetic number, because the mean of its divisors is an integer number (1115500996).

Almost surely, 2^2231001991 is an apocalyptic number.

2231001991 is a deficient number, since it is larger than the sum of its proper divisors (1).

2231001991 is an equidigital number, since it uses as much as digits as its factorization.

2231001991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 2231001991 is about 47233.4837906331. The cubic root of 2231001991 is about 1306.6722036663.

The spelling of 2231001991 in words is "two billion, two hundred thirty-one million, one thousand, nine hundred ninety-one".