775787561 has 2 divisors, whose sum is σ = 775787562. Its totient is φ = 775787560.

The previous prime is 775787531. The next prime is 775787567. The reversal of 775787561 is 165787577.

775787561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 504855961 + 270931600 = 22469^2 + 16460^2 .

It is a cyclic number.

It is not a de Polignac number, because 775787561 - 2²² = 771593257 is a prime.

It is not a weakly prime, because it can be changed into another prime (775787567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 387893780 + 387893781.

It is an arithmetic number, because the mean of its divisors is an integer number (387893781).

Almost surely, 2^775787561 is an apocalyptic number.

It is an amenable number.

775787561 is a deficient number, since it is larger than the sum of its proper divisors (1).

775787561 is an equidigital number, since it uses as much as digits as its factorization.

775787561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2881200, while the sum is 53.

The square root of 775787561 is about 27852.9632355338. The cubic root of 775787561 is about 918.8563139441.

The spelling of 775787561 in words is "seven hundred seventy-five million, seven hundred eighty-seven thousand, five hundred sixty-one".