1978558679 has 2 divisors, whose sum is σ = 1978558680. Its totient is φ = 1978558678.

The previous prime is 1978558649. The next prime is 1978558691. The reversal of 1978558679 is 9768558791.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1978558679 - 2¹² = 1978554583 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1978558619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 989279339 + 989279340.

It is an arithmetic number, because the mean of its divisors is an integer number (989279340).

Almost surely, 2^1978558679 is an apocalyptic number.

1978558679 is a deficient number, since it is larger than the sum of its proper divisors (1).

1978558679 is an equidigital number, since it uses as much as digits as its factorization.

1978558679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38102400, while the sum is 65.

The square root of 1978558679 is about 44480.9923338048. The cubic root of 1978558679 is about 1255.4024685485.

The spelling of 1978558679 in words is "one billion, nine hundred seventy-eight million, five hundred fifty-eight thousand, six hundred seventy-nine".