7943921664 has 224 divisors, whose sum is σ = 24637934976. Its totient is φ = 2229534720.

The previous prime is 7943921651. The next prime is 7943921669. The reversal of 7943921664 is 4661293497.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (224).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7943921669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10493574 + ... + 10494330.

Almost surely, 2^7943921664 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 7943921664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12318967488).

7943921664 is an abundant number, since it is smaller than the sum of its proper divisors (16694013312).

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

7943921664 is an equidigital number, since it uses as much as digits as its factorization.

7943921664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 854 (or 830 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 51.

The square root of 7943921664 is about 89128.6803672084. The cubic root of 7943921664 is about 1995.3158432358.

The spelling of 7943921664 in words is "seven billion, nine hundred forty-three million, nine hundred twenty-one thousand, six hundred sixty-four".