919229821 has 2 divisors, whose sum is σ = 919229822. Its totient is φ = 919229820.

The previous prime is 919229789. The next prime is 919229833. The reversal of 919229821 is 128922919.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 498405625 + 420824196 = 22325^2 + 20514^2 .

It is an emirp because it is prime and its reverse (128922919) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 919229821 - 2⁵ = 919229789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (919229621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 459614910 + 459614911.

It is an arithmetic number, because the mean of its divisors is an integer number (459614911).

Almost surely, 2^919229821 is an apocalyptic number.

It is an amenable number.

919229821 is a deficient number, since it is larger than the sum of its proper divisors (1).

919229821 is an equidigital number, since it uses as much as digits as its factorization.

919229821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46656, while the sum is 43.

The square root of 919229821 is about 30318.8030931302. The cubic root of 919229821 is about 972.3173491846.

The spelling of 919229821 in words is "nine hundred nineteen million, two hundred twenty-nine thousand, eight hundred twenty-one".