771783961 has 9 divisors (see below), whose sum is σ = 836109981. Its totient is φ = 712082592.

The previous prime is 771783949. The next prime is 771784001. The reversal of 771783961 is 169387177.

The square root of 771783961 is 27781.

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

It can be written as a sum of positive squares in 4 ways, for example, as 518973961 + 252810000 = 22781^2 + 15900^2 .

It is not a de Polignac number, because 771783961 - 2⁹ = 771783449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (771783941) 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 in 8 ways as a sum of consecutive naturals, for example, 360085 + ... + 362221.

It is an arithmetic number, because the mean of its divisors is an integer number (92901109).

Almost surely, 2^771783961 is an apocalyptic number.

771783961 is the 27781-st square number.

771783961 is the 13891-st centered octagonal number.

It is an amenable number.

771783961 is a deficient number, since it is larger than the sum of its proper divisors (64326020).

771783961 is an frugal number, since it uses more digits than its factorization.

771783961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4300 (or 2150 counting only the distinct ones).

The product of its digits is 444528, while the sum is 49.

The cubic root of 771783961 is about 917.2729424996.

Multiplying 771783961 by its sum of digits (49), we get a square (37817414089 = 194467²).

The spelling of 771783961 in words is "seven hundred seventy-one million, seven hundred eighty-three thousand, nine hundred sixty-one".