778556154949 has 2 divisors, whose sum is σ = 778556154950. Its totient is φ = 778556154948.

The previous prime is 778556154941. The next prime is 778556154953. The reversal of 778556154949 is 949451655877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 772653306049 + 5902848900 = 879007^2 + 76830^2 .

It is a cyclic number.

It is not a de Polignac number, because 778556154949 - 2³ = 778556154941 is a prime.

It is a super-2 number, since 2×778556154949² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (778556154941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 389278077474 + 389278077475.

It is an arithmetic number, because the mean of its divisors is an integer number (389278077475).

Almost surely, 2^778556154949 is an apocalyptic number.

It is an amenable number.

778556154949 is a deficient number, since it is larger than the sum of its proper divisors (1).

778556154949 is an equidigital number, since it uses as much as digits as its factorization.

778556154949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 381024000, while the sum is 70.

The spelling of 778556154949 in words is "seven hundred seventy-eight billion, five hundred fifty-six million, one hundred fifty-four thousand, nine hundred forty-nine".