111921661 has 2 divisors, whose sum is σ = 111921662. Its totient is φ = 111921660.

The previous prime is 111921619. The next prime is 111921713. The reversal of 111921661 is 166129111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 105062500 + 6859161 = 10250^2 + 2619^2 .

It is a cyclic number.

It is not a de Polignac number, because 111921661 - 2¹⁹ = 111397373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111931661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55960830 + 55960831.

It is an arithmetic number, because the mean of its divisors is an integer number (55960831).

Almost surely, 2^111921661 is an apocalyptic number.

It is an amenable number.

111921661 is a deficient number, since it is larger than the sum of its proper divisors (1).

111921661 is an equidigital number, since it uses as much as digits as its factorization.

111921661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 28.

The square root of 111921661 is about 10579.3034269748. The cubic root of 111921661 is about 481.9160408274.

The spelling of 111921661 in words is "one hundred eleven million, nine hundred twenty-one thousand, six hundred sixty-one".