1989411871 has 2 divisors, whose sum is σ = 1989411872. Its totient is φ = 1989411870.

The previous prime is 1989411839. The next prime is 1989411913. The reversal of 1989411871 is 1781149891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1989411871 - 2⁵ = 1989411839 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1989411821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994705935 + 994705936.

It is an arithmetic number, because the mean of its divisors is an integer number (994705936).

Almost surely, 2^1989411871 is an apocalyptic number.

1989411871 is a deficient number, since it is larger than the sum of its proper divisors (1).

1989411871 is an equidigital number, since it uses as much as digits as its factorization.

1989411871 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 49.

The square root of 1989411871 is about 44602.8235765405. The cubic root of 1989411871 is about 1257.6937469958.

The spelling of 1989411871 in words is "one billion, nine hundred eighty-nine million, four hundred eleven thousand, eight hundred seventy-one".