30778021 has 2 divisors, whose sum is σ = 30778022. Its totient is φ = 30778020.

The previous prime is 30777941. The next prime is 30778037. The reversal of 30778021 is 12087703.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24147396 + 6630625 = 4914^2 + 2575^2 .

It is an emirp because it is prime and its reverse (12087703) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 30778021 - 2⁷ = 30777893 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30778051) 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, 15389010 + 15389011.

It is an arithmetic number, because the mean of its divisors is an integer number (15389011).

Almost surely, 2^30778021 is an apocalyptic number.

It is an amenable number.

30778021 is a deficient number, since it is larger than the sum of its proper divisors (1).

30778021 is an equidigital number, since it uses as much as digits as its factorization.

30778021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 30778021 is about 5547.7942463649. The cubic root of 30778021 is about 313.3864613650.

The spelling of 30778021 in words is "thirty million, seven hundred seventy-eight thousand, twenty-one".