1531867391 has 2 divisors, whose sum is σ = 1531867392. Its totient is φ = 1531867390.

The previous prime is 1531867349. The next prime is 1531867409. The reversal of 1531867391 is 1937681351.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1531867391 - 2¹⁴ = 1531851007 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1531867291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 765933695 + 765933696.

It is an arithmetic number, because the mean of its divisors is an integer number (765933696).

Almost surely, 2^1531867391 is an apocalyptic number.

1531867391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1531867391 is an equidigital number, since it uses as much as digits as its factorization.

1531867391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 136080, while the sum is 44.

The square root of 1531867391 is about 39139.0775440607. The cubic root of 1531867391 is about 1152.7639606011.

The spelling of 1531867391 in words is "one billion, five hundred thirty-one million, eight hundred sixty-seven thousand, three hundred ninety-one".