7777561680 has 400 divisors, whose sum is σ = 31033073280. Its totient is φ = 1768449024.

The previous prime is 7777561679. The next prime is 7777561699. The reversal of 7777561680 is 861657777.

7777561680 is a `hidden beast` number, since 7 + 7 + 77 + 561 + 6 + 8 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 12564411 + ... + 12565029.

Almost surely, 2^7777561680 is an apocalyptic number.

7777561680 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 7777561680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15516536640).

7777561680 is an abundant number, since it is smaller than the sum of its proper divisors (23255511600).

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

7777561680 is a wasteful number, since it uses less digits than its factorization.

7777561680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 928 (or 913 counting only the distinct ones).

The product of its (nonzero) digits is 3457440, while the sum is 54.

The square root of 7777561680 is about 88190.4852010692. The cubic root of 7777561680 is about 1981.2889678703.

The spelling of 7777561680 in words is "seven billion, seven hundred seventy-seven million, five hundred sixty-one thousand, six hundred eighty".