842638393 has 2 divisors, whose sum is σ = 842638394. Its totient is φ = 842638392.

The previous prime is 842638339. The next prime is 842638421. The reversal of 842638393 is 393836248.

Together with previous prime (842638339) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 820707904 + 21930489 = 28648^2 + 4683^2 .

It is a cyclic number.

It is not a de Polignac number, because 842638393 - 2⁹ = 842637881 is a prime.

It is a super-2 number, since 2×842638393² = 1420078922715244898, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (842636393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 421319196 + 421319197.

It is an arithmetic number, because the mean of its divisors is an integer number (421319197).

Almost surely, 2^842638393 is an apocalyptic number.

It is an amenable number.

842638393 is a deficient number, since it is larger than the sum of its proper divisors (1).

842638393 is an equidigital number, since it uses as much as digits as its factorization.

842638393 is an evil number, because the sum of its binary digits is even.

The product of its digits is 746496, while the sum is 46.

The square root of 842638393 is about 29028.2344106561. The cubic root of 842638393 is about 944.5256311072.

The spelling of 842638393 in words is "eight hundred forty-two million, six hundred thirty-eight thousand, three hundred ninety-three".