775243520921 has 2 divisors, whose sum is σ = 775243520922. Its totient is φ = 775243520920.

The previous prime is 775243520819. The next prime is 775243520927. The reversal of 775243520921 is 129025342577.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 475459895296 + 299783625625 = 689536^2 + 547525^2 .

It is a cyclic number.

It is not a de Polignac number, because 775243520921 - 2³⁸ = 500365613977 is a prime.

It is not a weakly prime, because it can be changed into another prime (775243520927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 387621760460 + 387621760461.

It is an arithmetic number, because the mean of its divisors is an integer number (387621760461).

Almost surely, 2^775243520921 is an apocalyptic number.

It is an amenable number.

775243520921 is a deficient number, since it is larger than the sum of its proper divisors (1).

775243520921 is an equidigital number, since it uses as much as digits as its factorization.

775243520921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1058400, while the sum is 47.

The spelling of 775243520921 in words is "seven hundred seventy-five billion, two hundred forty-three million, five hundred twenty thousand, nine hundred twenty-one".