1242779778 has 24 divisors (see below), whose sum is σ = 2834410800. Its totient is φ = 392456664.

The previous prime is 1242779773. The next prime is 1242779789. The reversal of 1242779778 is 8779772421.

It is not an unprimeable number, because it can be changed into a prime (1242779773) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1816588 + ... + 1817271.

It is an arithmetic number, because the mean of its divisors is an integer number (118100450).

Almost surely, 2^1242779778 is an apocalyptic number.

1242779778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1242779778 is an abundant number, since it is smaller than the sum of its proper divisors (1591631022).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1242779778 is a wasteful number, since it uses less digits than its factorization.

1242779778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3633886 (or 3633883 counting only the distinct ones).

The product of its digits is 2765952, while the sum is 54.

The square root of 1242779778 is about 35253.0818227286. The cubic root of 1242779778 is about 1075.1392725271.

The spelling of 1242779778 in words is "one billion, two hundred forty-two million, seven hundred seventy-nine thousand, seven hundred seventy-eight".