9778250821 has 2 divisors, whose sum is σ = 9778250822. Its totient is φ = 9778250820.

The previous prime is 9778250771. The next prime is 9778250837. The reversal of 9778250821 is 1280528779.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9503520196 + 274730625 = 97486^2 + 16575^2 .

It is a cyclic number.

It is not a de Polignac number, because 9778250821 - 2¹⁵ = 9778218053 is a prime.

It is a super-2 number, since 2×9778250821² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9778250891) 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, 4889125410 + 4889125411.

It is an arithmetic number, because the mean of its divisors is an integer number (4889125411).

Almost surely, 2^9778250821 is an apocalyptic number.

It is an amenable number.

9778250821 is a deficient number, since it is larger than the sum of its proper divisors (1).

9778250821 is an equidigital number, since it uses as much as digits as its factorization.

9778250821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 564480, while the sum is 49.

The square root of 9778250821 is about 98885.0384082446. The cubic root of 9778250821 is about 2138.3907035860.

The spelling of 9778250821 in words is "nine billion, seven hundred seventy-eight million, two hundred fifty thousand, eight hundred twenty-one".