111721979 has 4 divisors (see below), whose sum is σ = 113295600. Its totient is φ = 110148360.

The previous prime is 111721963. The next prime is 111721997. The reversal of 111721979 is 979127111.

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 111721979 - 2⁴ = 111721963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (111751979) 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, 786704 + ... + 786845.

It is an arithmetic number, because the mean of its divisors is an integer number (28323900).

Almost surely, 2^111721979 is an apocalyptic number.

111721979 is a deficient number, since it is larger than the sum of its proper divisors (1573621).

111721979 is an equidigital number, since it uses as much as digits as its factorization.

111721979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1573620.

The product of its digits is 7938, while the sum is 38.

The square root of 111721979 is about 10569.8618250193. The cubic root of 111721979 is about 481.6292710651.

The spelling of 111721979 in words is "one hundred eleven million, seven hundred twenty-one thousand, nine hundred seventy-nine".