1242139477 has 2 divisors, whose sum is σ = 1242139478. Its totient is φ = 1242139476.

The previous prime is 1242139471. The next prime is 1242139517. The reversal of 1242139477 is 7749312421.

It is a happy number.

It is an a-pointer prime, because the next prime (1242139517) can be obtained adding 1242139477 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1159674916 + 82464561 = 34054^2 + 9081^2 .

It is a cyclic number.

It is not a de Polignac number, because 1242139477 - 2¹⁵ = 1242106709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1242139471) 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, 621069738 + 621069739.

It is an arithmetic number, because the mean of its divisors is an integer number (621069739).

Almost surely, 2^1242139477 is an apocalyptic number.

It is an amenable number.

1242139477 is a deficient number, since it is larger than the sum of its proper divisors (1).

1242139477 is an equidigital number, since it uses as much as digits as its factorization.

1242139477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84672, while the sum is 40.

The square root of 1242139477 is about 35243.9991629781. Note that the first 3 decimals coincide. The cubic root of 1242139477 is about 1074.9545975416.

The spelling of 1242139477 in words is "one billion, two hundred forty-two million, one hundred thirty-nine thousand, four hundred seventy-seven".