776621664 has 144 divisors (see below), whose sum is σ = 2718267552. Its totient is φ = 204816384.

The previous prime is 776621663. The next prime is 776621689. The reversal of 776621664 is 466126677.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (144).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (776621663) 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 23 ways as a sum of consecutive naturals, for example, 11392 + ... + 41024.

It is an arithmetic number, because the mean of its divisors is an integer number (18876858).

Almost surely, 2^776621664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 776621664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1359133776).

776621664 is an abundant number, since it is smaller than the sum of its proper divisors (1941645888).

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

776621664 is a wasteful number, since it uses less digits than its factorization.

776621664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29669 (or 29658 counting only the distinct ones).

The product of its digits is 508032, while the sum is 45.

The square root of 776621664 is about 27867.9325390313. The cubic root of 776621664 is about 919.1855047059.

The spelling of 776621664 in words is "seven hundred seventy-six million, six hundred twenty-one thousand, six hundred sixty-four".