783138821 has 2 divisors, whose sum is σ = 783138822. Its totient is φ = 783138820.

The previous prime is 783138809. The next prime is 783138869. The reversal of 783138821 is 128831387.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 679384225 + 103754596 = 26065^2 + 10186^2 .

It is an emirp because it is prime and its reverse (128831387) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 783138821 - 2⁶ = 783138757 is a prime.

It is a super-2 number, since 2×783138821² = 1226612825914540082, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (783138871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 391569410 + 391569411.

It is an arithmetic number, because the mean of its divisors is an integer number (391569411).

Almost surely, 2^783138821 is an apocalyptic number.

It is an amenable number.

783138821 is a deficient number, since it is larger than the sum of its proper divisors (1).

783138821 is an equidigital number, since it uses as much as digits as its factorization.

783138821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64512, while the sum is 41.

The square root of 783138821 is about 27984.6175782339. The cubic root of 783138821 is about 921.7495147417.

The spelling of 783138821 in words is "seven hundred eighty-three million, one hundred thirty-eight thousand, eight hundred twenty-one".