1279690189 has 2 divisors, whose sum is σ = 1279690190. Its totient is φ = 1279690188.

The previous prime is 1279690187. The next prime is 1279690211. The reversal of 1279690189 is 9810969721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1261457289 + 18232900 = 35517^2 + 4270^2 .

It is a cyclic number.

It is not a de Polignac number, because 1279690189 - 2¹ = 1279690187 is a prime.

Together with 1279690187, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1279690187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639845094 + 639845095.

It is an arithmetic number, because the mean of its divisors is an integer number (639845095).

Almost surely, 2^1279690189 is an apocalyptic number.

It is an amenable number.

1279690189 is a deficient number, since it is larger than the sum of its proper divisors (1).

1279690189 is an equidigital number, since it uses as much as digits as its factorization.

1279690189 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 489888, while the sum is 52.

The square root of 1279690189 is about 35772.7576376214. The cubic root of 1279690189 is about 1085.6794399407.

The spelling of 1279690189 in words is "one billion, two hundred seventy-nine million, six hundred ninety thousand, one hundred eighty-nine".