921807109 has 2 divisors, whose sum is σ = 921807110. Its totient is φ = 921807108.

The previous prime is 921807071. The next prime is 921807113. The reversal of 921807109 is 901708129.

921807109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 846984609 + 74822500 = 29103^2 + 8650^2 .

It is a cyclic number.

It is not a de Polignac number, because 921807109 - 2²¹ = 919709957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (921807119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460903554 + 460903555.

It is an arithmetic number, because the mean of its divisors is an integer number (460903555).

Almost surely, 2^921807109 is an apocalyptic number.

It is an amenable number.

921807109 is a deficient number, since it is larger than the sum of its proper divisors (1).

921807109 is an equidigital number, since it uses as much as digits as its factorization.

921807109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 921807109 is about 30361.2764718481. The cubic root of 921807109 is about 973.2252119088.

The spelling of 921807109 in words is "nine hundred twenty-one million, eight hundred seven thousand, one hundred nine".