111907721 has 4 divisors (see below), whose sum is σ = 114932292. Its totient is φ = 108883152.

The previous prime is 111907699. The next prime is 111907727. The reversal of 111907721 is 127709111.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127709111 = 2659 ⋅48029.

It can be written as a sum of positive squares in 2 ways, for example, as 92371321 + 19536400 = 9611^2 + 4420^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111907721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (111907727) 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, 1512230 + ... + 1512303.

It is an arithmetic number, because the mean of its divisors is an integer number (28733073).

Almost surely, 2^111907721 is an apocalyptic number.

It is an amenable number.

111907721 is a deficient number, since it is larger than the sum of its proper divisors (3024571).

111907721 is an equidigital number, since it uses as much as digits as its factorization.

111907721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3024570.

The product of its (nonzero) digits is 882, while the sum is 29.

The square root of 111907721 is about 10578.6445729120. The cubic root of 111907721 is about 481.8960322235.

The spelling of 111907721 in words is "one hundred eleven million, nine hundred seven thousand, seven hundred twenty-one".