1989148591 has 2 divisors, whose sum is σ = 1989148592. Its totient is φ = 1989148590.

The previous prime is 1989148571. The next prime is 1989148607. The reversal of 1989148591 is 1958419891.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1989148591 - 2⁵ = 1989148559 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1989148501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994574295 + 994574296.

It is an arithmetic number, because the mean of its divisors is an integer number (994574296).

Almost surely, 2^1989148591 is an apocalyptic number.

1989148591 is a deficient number, since it is larger than the sum of its proper divisors (1).

1989148591 is an equidigital number, since it uses as much as digits as its factorization.

1989148591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 933120, while the sum is 55.

The square root of 1989148591 is about 44599.8720962292. The cubic root of 1989148591 is about 1257.6382632248.

The spelling of 1989148591 in words is "one billion, nine hundred eighty-nine million, one hundred forty-eight thousand, five hundred ninety-one".