771855980 has 72 divisors (see below), whose sum is σ = 1914472224. Its totient is φ = 256055040.

The previous prime is 771855961. The next prime is 771856027. The reversal of 771855980 is 89558177.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 131672 + ... + 137408.

It is an arithmetic number, because the mean of its divisors is an integer number (26589892).

Almost surely, 2^771855980 is an apocalyptic number.

771855980 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 771855980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (957236112).

771855980 is an abundant number, since it is smaller than the sum of its proper divisors (1142616244).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

771855980 is a wasteful number, since it uses less digits than its factorization.

771855980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5815 (or 5782 counting only the distinct ones).

The product of its (nonzero) digits is 705600, while the sum is 50.

The square root of 771855980 is about 27782.2961614047. The cubic root of 771855980 is about 917.3014733790.

The spelling of 771855980 in words is "seven hundred seventy-one million, eight hundred fifty-five thousand, nine hundred eighty".