1491000391 has 2 divisors, whose sum is σ = 1491000392. Its totient is φ = 1491000390.

The previous prime is 1491000373. The next prime is 1491000439. The reversal of 1491000391 is 1930001941.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1491000391 - 2⁹ = 1490999879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1491000191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 745500195 + 745500196.

It is an arithmetic number, because the mean of its divisors is an integer number (745500196).

Almost surely, 2^1491000391 is an apocalyptic number.

1491000391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1491000391 is an equidigital number, since it uses as much as digits as its factorization.

1491000391 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 1491000391 is about 38613.4742156155. The cubic root of 1491000391 is about 1142.4203197499.

The spelling of 1491000391 in words is "one billion, four hundred ninety-one million, three hundred ninety-one", and thus it is an aban number.