7979981856 has 384 divisors, whose sum is σ = 27051687936. Its totient is φ = 1999918080.

The previous prime is 7979981803. The next prime is 7979981857. The reversal of 7979981856 is 6581899797.

It is a super-2 number, since 2×7979981856² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7979981857) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 35784561 + ... + 35784783.

It is an arithmetic number, because the mean of its divisors is an integer number (70447104).

Almost surely, 2^7979981856 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 7979981856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13525843968).

7979981856 is an abundant number, since it is smaller than the sum of its proper divisors (19071706080).

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

7979981856 is a wasteful number, since it uses less digits than its factorization.

7979981856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404 (or 396 counting only the distinct ones).

The product of its digits is 68584320, while the sum is 69.

The square root of 7979981856 is about 89330.7441813847. The cubic root of 7979981856 is about 1998.3304279858.

The spelling of 7979981856 in words is "seven billion, nine hundred seventy-nine million, nine hundred eighty-one thousand, eight hundred fifty-six".