123998779 has 4 divisors (see below), whose sum is σ = 124083000. Its totient is φ = 123914560.

The previous prime is 123998761. The next prime is 123998789. The reversal of 123998779 is 977899321.

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

It is a cyclic number.

It is not a de Polignac number, because 123998779 - 2²¹ = 121901627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123998759) 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 in 3 ways as a sum of consecutive naturals, for example, 39862 + ... + 42859.

It is an arithmetic number, because the mean of its divisors is an integer number (31020750).

Almost surely, 2^123998779 is an apocalyptic number.

123998779 is a deficient number, since it is larger than the sum of its proper divisors (84221).

123998779 is an equidigital number, since it uses as much as digits as its factorization.

123998779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84220.

The product of its digits is 1714608, while the sum is 55.

The square root of 123998779 is about 11135.4739010066. The cubic root of 123998779 is about 498.6614584775.

The spelling of 123998779 in words is "one hundred twenty-three million, nine hundred ninety-eight thousand, seven hundred seventy-nine".