111645721 has 4 divisors (see below), whose sum is σ = 121795344. Its totient is φ = 101496100.

The previous prime is 111645713. The next prime is 111645731. The reversal of 111645721 is 127546111.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 111645721 - 2³ = 111645713 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 111645721.

It is not an unprimeable number, because it can be changed into a prime (111645731) 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, 5074795 + ... + 5074816.

It is an arithmetic number, because the mean of its divisors is an integer number (30448836).

Almost surely, 2^111645721 is an apocalyptic number.

111645721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

111645721 is a deficient number, since it is larger than the sum of its proper divisors (10149623).

111645721 is a wasteful number, since it uses less digits than its factorization.

111645721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10149622.

The product of its digits is 1680, while the sum is 28.

The square root of 111645721 is about 10566.2538773209. The cubic root of 111645721 is about 481.5196643284.

The spelling of 111645721 in words is "one hundred eleven million, six hundred forty-five thousand, seven hundred twenty-one".