1979991289 has 2 divisors, whose sum is σ = 1979991290. Its totient is φ = 1979991288.

The previous prime is 1979991283. The next prime is 1979991301. The reversal of 1979991289 is 9821999791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1758963600 + 221027689 = 41940^2 + 14867^2 .

It is a cyclic number.

It is not a de Polignac number, because 1979991289 - 2²⁷ = 1845773561 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1979991289.

It is not a weakly prime, because it can be changed into another prime (1979991283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 989995644 + 989995645.

It is an arithmetic number, because the mean of its divisors is an integer number (989995645).

Almost surely, 2^1979991289 is an apocalyptic number.

It is an amenable number.

1979991289 is a deficient number, since it is larger than the sum of its proper divisors (1).

1979991289 is an equidigital number, since it uses as much as digits as its factorization.

1979991289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6613488, while the sum is 64.

The square root of 1979991289 is about 44497.0930398830. The cubic root of 1979991289 is about 1255.7053941486.

The spelling of 1979991289 in words is "one billion, nine hundred seventy-nine million, nine hundred ninety-one thousand, two hundred eighty-nine".