919789921 has 2 divisors, whose sum is σ = 919789922. Its totient is φ = 919789920.

The previous prime is 919789901. The next prime is 919789967. The reversal of 919789921 is 129987919.

919789921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 594384400 + 325405521 = 24380^2 + 18039^2 .

It is a cyclic number.

It is not a de Polignac number, because 919789921 - 2¹⁷ = 919658849 is a prime.

It is not a weakly prime, because it can be changed into another prime (919789901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 459894960 + 459894961.

It is an arithmetic number, because the mean of its divisors is an integer number (459894961).

Almost surely, 2^919789921 is an apocalyptic number.

It is an amenable number.

919789921 is a deficient number, since it is larger than the sum of its proper divisors (1).

919789921 is an equidigital number, since it uses as much as digits as its factorization.

919789921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 734832, while the sum is 55.

The square root of 919789921 is about 30328.0385287278. The cubic root of 919789921 is about 972.5147914210.

The spelling of 919789921 in words is "nine hundred nineteen million, seven hundred eighty-nine thousand, nine hundred twenty-one".