8421540840 has 320 divisors, whose sum is σ = 29920492800. Its totient is φ = 2121057792.

The previous prime is 8421540839. The next prime is 8421540847. The reversal of 8421540840 is 480451248.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 8421540795 and 8421540804.

It is not an unprimeable number, because it can be changed into a prime (8421540847) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 4415167 + ... + 4417073.

It is an arithmetic number, because the mean of its divisors is an integer number (93501540).

Almost surely, 2^8421540840 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 8421540840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14960246400).

8421540840 is an abundant number, since it is smaller than the sum of its proper divisors (21498951960).

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

8421540840 is a wasteful number, since it uses less digits than its factorization.

8421540840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2006 (or 1993 counting only the distinct ones).

The product of its (nonzero) digits is 40960, while the sum is 36.

The square root of 8421540840 is about 91768.9535736351. The cubic root of 8421540840 is about 2034.5288519632.

The spelling of 8421540840 in words is "eight billion, four hundred twenty-one million, five hundred forty thousand, eight hundred forty".