838197721 has 2 divisors, whose sum is σ = 838197722. Its totient is φ = 838197720.

The previous prime is 838197713. The next prime is 838197761. The reversal of 838197721 is 127791838.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 805935321 + 32262400 = 28389^2 + 5680^2 .

It is a cyclic number.

It is not a de Polignac number, because 838197721 - 2³ = 838197713 is a prime.

It is not a weakly prime, because it can be changed into another prime (838197761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 419098860 + 419098861.

It is an arithmetic number, because the mean of its divisors is an integer number (419098861).

Almost surely, 2^838197721 is an apocalyptic number.

It is an amenable number.

838197721 is a deficient number, since it is larger than the sum of its proper divisors (1).

838197721 is an equidigital number, since it uses as much as digits as its factorization.

838197721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 169344, while the sum is 46.

The square root of 838197721 is about 28951.6445301472. The cubic root of 838197721 is about 942.8635032836.

The spelling of 838197721 in words is "eight hundred thirty-eight million, one hundred ninety-seven thousand, seven hundred twenty-one".