1239978779 has 16 divisors (see below), whose sum is σ = 1406942880. Its totient is φ = 1083352320.

The previous prime is 1239978757. The next prime is 1239978799. The reversal of 1239978779 is 9778799321.

It is a cyclic number.

It is not a de Polignac number, because 1239978779 - 2²⁸ = 971543323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1239978709) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 423629 + ... + 426545.

It is an arithmetic number, because the mean of its divisors is an integer number (87933930).

Almost surely, 2^1239978779 is an apocalyptic number.

1239978779 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1239978779 is a deficient number, since it is larger than the sum of its proper divisors (166964101).

1239978779 is a wasteful number, since it uses less digits than its factorization.

1239978779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4670.

The product of its digits is 12002256, while the sum is 62.

The square root of 1239978779 is about 35213.3324040767. The cubic root of 1239978779 is about 1074.3309423231.

The spelling of 1239978779 in words is "one billion, two hundred thirty-nine million, nine hundred seventy-eight thousand, seven hundred seventy-nine".