775991664 has 200 divisors, whose sum is σ = 2679114240. Its totient is φ = 212015232.

The previous prime is 775991647. The next prime is 775991669. The reversal of 775991664 is 466199577.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 775991664.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (775991669) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 206797 + ... + 210515.

Almost surely, 2^775991664 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 775991664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1339557120).

775991664 is an abundant number, since it is smaller than the sum of its proper divisors (1903122576).

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

775991664 is a wasteful number, since it uses less digits than its factorization.

775991664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3769 (or 3754 counting only the distinct ones).

The product of its digits is 2857680, while the sum is 54.

The square root of 775991664 is about 27856.6269314862. The cubic root of 775991664 is about 918.9368879291.

The spelling of 775991664 in words is "seven hundred seventy-five million, nine hundred ninety-one thousand, six hundred sixty-four".