1240331891 has 2 divisors, whose sum is σ = 1240331892. Its totient is φ = 1240331890.

The previous prime is 1240331887. The next prime is 1240331893. The reversal of 1240331891 is 1981330421.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1240331891 - 2² = 1240331887 is a prime.

Together with 1240331893, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1240331893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 620165945 + 620165946.

It is an arithmetic number, because the mean of its divisors is an integer number (620165946).

Almost surely, 2^1240331891 is an apocalyptic number.

1240331891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1240331891 is an equidigital number, since it uses as much as digits as its factorization.

1240331891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 1240331891 is about 35218.3459435562. The cubic root of 1240331891 is about 1074.4329126550.

The spelling of 1240331891 in words is "one billion, two hundred forty million, three hundred thirty-one thousand, eight hundred ninety-one".