9928939779 has 24 divisors (see below), whose sum is σ = 15707974464. Its totient is φ = 5993550000.

The previous prime is 9928939733. The next prime is 9928939789. The reversal of 9928939779 is 9779398299.

9928939779 is a `hidden beast` number, since 9 + 92 + 89 + 397 + 79 = 666.

It is not a de Polignac number, because 9928939779 - 2⁷ = 9928939651 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9928939789) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 174937 + ... + 224634.

It is an arithmetic number, because the mean of its divisors is an integer number (654498936).

Almost surely, 2^9928939779 is an apocalyptic number.

9928939779 is a gapful number since it is divisible by the number (99) formed by its first and last digit.

9928939779 is a deficient number, since it is larger than the sum of its proper divisors (5779034685).

9928939779 is a wasteful number, since it uses less digits than its factorization.

9928939779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399839 (or 399836 counting only the distinct ones).

The product of its digits is 138883248, while the sum is 72.

The square root of 9928939779 is about 99644.0654479734. The cubic root of 9928939779 is about 2149.3194008709.

The spelling of 9928939779 in words is "nine billion, nine hundred twenty-eight million, nine hundred thirty-nine thousand, seven hundred seventy-nine".