1242123979 has 2 divisors, whose sum is σ = 1242123980. Its totient is φ = 1242123978.

The previous prime is 1242123977. The next prime is 1242124007. The reversal of 1242123979 is 9793212421.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1242123979 - 2¹ = 1242123977 is a prime.

Together with 1242123977, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1242123977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621061989 + 621061990.

It is an arithmetic number, because the mean of its divisors is an integer number (621061990).

Almost surely, 2^1242123979 is an apocalyptic number.

1242123979 is a deficient number, since it is larger than the sum of its proper divisors (1).

1242123979 is an equidigital number, since it uses as much as digits as its factorization.

1242123979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 40.

The square root of 1242123979 is about 35243.7792950756. The cubic root of 1242123979 is about 1074.9501268371.

The spelling of 1242123979 in words is "one billion, two hundred forty-two million, one hundred twenty-three thousand, nine hundred seventy-nine".