1242778717 has 4 divisors (see below), whose sum is σ = 1242922716. Its totient is φ = 1242634720.

The previous prime is 1242778697. The next prime is 1242778759. The reversal of 1242778717 is 7178772421.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 929701081 + 313077636 = 30491^2 + 17694^2 .

It is a cyclic number.

It is not a de Polignac number, because 1242778717 - 2²³ = 1234390109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1242778417) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58168 + ... + 76609.

It is an arithmetic number, because the mean of its divisors is an integer number (310730679).

Almost surely, 2^1242778717 is an apocalyptic number.

It is an amenable number.

1242778717 is a deficient number, since it is larger than the sum of its proper divisors (143999).

1242778717 is an equidigital number, since it uses as much as digits as its factorization.

1242778717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143998.

The product of its digits is 307328, while the sum is 46.

The square root of 1242778717 is about 35253.0667743957. The cubic root of 1242778717 is about 1075.1389665670.

The spelling of 1242778717 in words is "one billion, two hundred forty-two million, seven hundred seventy-eight thousand, seven hundred seventeen".