777625912561 has 9 divisors (see below), whose sum is σ = 785491375179. Its totient is φ = 769838463000.

The previous prime is 777625912559. The next prime is 777625912603. The reversal of 777625912561 is 165219526777.

The square root of 777625912561 is 881831.

It is a perfect power (a square), and thus also a powerful number.

777625912561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 747133768161 + 30492144400 = 864369^2 + 174620^2 .

It is not a de Polignac number, because 777625912561 - 2¹ = 777625912559 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 777625912496 and 777625912505.

It is not an unprimeable number, because it can be changed into a prime (777625912541) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 89060566 + ... + 89069296.

Almost surely, 2^777625912561 is an apocalyptic number.

777625912561 is the 881831-st square number.

777625912561 is the 440916-th centered octagonal number.

It is an amenable number.

777625912561 is a deficient number, since it is larger than the sum of its proper divisors (7865462618).

777625912561 is an frugal number, since it uses more digits than its factorization.

777625912561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17664 (or 8832 counting only the distinct ones).

The product of its digits is 11113200, while the sum is 58.

The spelling of 777625912561 in words is "seven hundred seventy-seven billion, six hundred twenty-five million, nine hundred twelve thousand, five hundred sixty-one".