7999639920 has 320 divisors, whose sum is σ = 29136230400. Its totient is φ = 2011806720.

The previous prime is 7999639919. The next prime is 7999639943. The reversal of 7999639920 is 299369997.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 17277609 + ... + 17278071.

It is an arithmetic number, because the mean of its divisors is an integer number (91050720).

Almost surely, 2^7999639920 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 7999639920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14568115200).

7999639920 is an abundant number, since it is smaller than the sum of its proper divisors (21136590480).

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

7999639920 is a wasteful number, since it uses less digits than its factorization.

7999639920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 925 (or 913 counting only the distinct ones).

The product of its (nonzero) digits is 14880348, while the sum is 63.

The square root of 7999639920 is about 89440.7061689475. The cubic root of 7999639920 is about 1999.9699928831.

The spelling of 7999639920 in words is "seven billion, nine hundred ninety-nine million, six hundred thirty-nine thousand, nine hundred twenty".