1242123977 has 2 divisors, whose sum is σ = 1242123978. Its totient is φ = 1242123976.
The previous prime is 1242123959. The next prime is 1242123979. The reversal of 1242123977 is 7793212421.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 805481161 + 436642816 = 28381^2 + 20896^2 .
It is a cyclic number.
It is not a de Polignac number, because 1242123977 - 210 = 1242122953 is a prime.
Together with 1242123979, it forms a pair of twin primes.
It is a Chen prime.
It is a self number, because there is not a number n which added to its sum of digits gives 1242123977.
It is not a weakly prime, because it can be changed into another prime (1242123979) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621061988 + 621061989.
It is an arithmetic number, because the mean of its divisors is an integer number (621061989).
Almost surely, 21242123977 is an apocalyptic number.
It is an amenable number.
1242123977 is a deficient number, since it is larger than the sum of its proper divisors (1).
1242123977 is an equidigital number, since it uses as much as digits as its factorization.
1242123977 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 42336, while the sum is 38.
The square root of 1242123977 is about 35243.7792667018. The cubic root of 1242123977 is about 1074.9501262602.
The spelling of 1242123977 in words is "one billion, two hundred forty-two million, one hundred twenty-three thousand, nine hundred seventy-seven".
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