7920391680 has 640 divisors, whose sum is σ = 30601612800. Its totient is φ = 1934917632.

The previous prime is 7920391669. The next prime is 7920391727. The reversal of 7920391680 is 861930297.

It is a tau number, because it is divible by the number of its divisors (640).

It is a super-2 number, since 2×7920391680² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 48591279 + ... + 48591441.

It is an arithmetic number, because the mean of its divisors is an integer number (47815020).

Almost surely, 2^7920391680 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 7920391680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15300806400).

7920391680 is an abundant number, since it is smaller than the sum of its proper divisors (22681221120).

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

7920391680 is a wasteful number, since it uses less digits than its factorization.

7920391680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251 (or 229 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The square root of 7920391680 is about 88996.5824062924. The cubic root of 7920391680 is about 1993.3438457131.

The spelling of 7920391680 in words is "seven billion, nine hundred twenty million, three hundred ninety-one thousand, six hundred eighty".