1491871687 has 2 divisors, whose sum is σ = 1491871688. Its totient is φ = 1491871686.

The previous prime is 1491871657. The next prime is 1491871729. The reversal of 1491871687 is 7861781941.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1491871687 - 2¹⁹ = 1491347399 is a prime.

It is a super-2 number, since 2×1491871687² = 4451362260944451938, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1491871607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 745935843 + 745935844.

It is an arithmetic number, because the mean of its divisors is an integer number (745935844).

Almost surely, 2^1491871687 is an apocalyptic number.

1491871687 is a deficient number, since it is larger than the sum of its proper divisors (1).

1491871687 is an equidigital number, since it uses as much as digits as its factorization.

1491871687 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 677376, while the sum is 52.

The square root of 1491871687 is about 38624.7548471184. The cubic root of 1491871687 is about 1142.6428084969.

The spelling of 1491871687 in words is "one billion, four hundred ninety-one million, eight hundred seventy-one thousand, six hundred eighty-seven".