109891921 has 2 divisors, whose sum is σ = 109891922. Its totient is φ = 109891920.

The previous prime is 109891879. The next prime is 109891973. The reversal of 109891921 is 129198901.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57532225 + 52359696 = 7585^2 + 7236^2 .

It is a cyclic number.

It is not a de Polignac number, because 109891921 - 2⁹ = 109891409 is a prime.

It is not a weakly prime, because it can be changed into another prime (109891981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54945960 + 54945961.

It is an arithmetic number, because the mean of its divisors is an integer number (54945961).

Almost surely, 2^109891921 is an apocalyptic number.

It is an amenable number.

109891921 is a deficient number, since it is larger than the sum of its proper divisors (1).

109891921 is an equidigital number, since it uses as much as digits as its factorization.

109891921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 40.

The square root of 109891921 is about 10482.9347512994. The cubic root of 109891921 is about 478.9850094753.

The spelling of 109891921 in words is "one hundred nine million, eight hundred ninety-one thousand, nine hundred twenty-one".