921091729 has 2 divisors, whose sum is σ = 921091730. Its totient is φ = 921091728.

The previous prime is 921091711. The next prime is 921091783. The reversal of 921091729 is 927190129.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 550606225 + 370485504 = 23465^2 + 19248^2 .

It is a cyclic number.

It is not a de Polignac number, because 921091729 - 2⁵ = 921091697 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 921091691 and 921091700.

It is not a weakly prime, because it can be changed into another prime (921091789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460545864 + 460545865.

It is an arithmetic number, because the mean of its divisors is an integer number (460545865).

Almost surely, 2^921091729 is an apocalyptic number.

It is an amenable number.

921091729 is a deficient number, since it is larger than the sum of its proper divisors (1).

921091729 is an equidigital number, since it uses as much as digits as its factorization.

921091729 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20412, while the sum is 40.

The square root of 921091729 is about 30349.4930600167. The cubic root of 921091729 is about 972.9733855314.

The spelling of 921091729 in words is "nine hundred twenty-one million, ninety-one thousand, seven hundred twenty-nine".