7721655816 has 128 divisors (see below), whose sum is σ = 23392385280. Its totient is φ = 2073501696.

The previous prime is 7721655779. The next prime is 7721655847. The reversal of 7721655816 is 6185561277.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2720350 + ... + 2723186.

It is an arithmetic number, because the mean of its divisors is an integer number (182753010).

Almost surely, 2^7721655816 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 7721655816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11696192640).

7721655816 is an abundant number, since it is smaller than the sum of its proper divisors (15670729464).

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

7721655816 is a wasteful number, since it uses less digits than its factorization.

7721655816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3823 (or 3819 counting only the distinct ones).

The product of its digits is 705600, while the sum is 48.

The square root of 7721655816 is about 87872.9526987685. The cubic root of 7721655816 is about 1976.5303155999.

The spelling of 7721655816 in words is "seven billion, seven hundred twenty-one million, six hundred fifty-five thousand, eight hundred sixteen".