7821921042 has 96 divisors (see below), whose sum is σ = 18961278336. Its totient is φ = 2314771200.

The previous prime is 7821920999. The next prime is 7821921049. The reversal of 7821921042 is 2401291287.

7821921042 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×7821921042² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 7821920988 and 7821921006.

It is not an unprimeable number, because it can be changed into a prime (7821921049) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 675433 + ... + 686915.

It is an arithmetic number, because the mean of its divisors is an integer number (197513316).

Almost surely, 2^7821921042 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7821921042, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9480639168).

7821921042 is an abundant number, since it is smaller than the sum of its proper divisors (11139357294).

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

7821921042 is a wasteful number, since it uses less digits than its factorization.

7821921042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11616 (or 11613 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 7821921042 is about 88441.6250529127. The cubic root of 7821921042 is about 1985.0485930743.

The spelling of 7821921042 in words is "seven billion, eight hundred twenty-one million, nine hundred twenty-one thousand, forty-two".