8521240 has 64 divisors (see below), whose sum is σ = 23607360. Its totient is φ = 2695680.

The previous prime is 8521237. The next prime is 8521243. The reversal of 8521240 is 421258.

It is an interprime number because it is at equal distance from previous prime (8521237) and next prime (8521243).

It is a super-2 number, since 2×8521240² = 145223062275200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8521243) 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, 2470 + ... + 4810.

It is an arithmetic number, because the mean of its divisors is an integer number (368865).

Almost surely, 2^8521240 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 8521240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11803680).

8521240 is an abundant number, since it is smaller than the sum of its proper divisors (15086120).

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

8521240 is a wasteful number, since it uses less digits than its factorization.

8521240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2372 (or 2368 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 22.

The square root of 8521240 is about 2919.1163046374. The cubic root of 8521240 is about 204.2526026314.

Adding to 8521240 its reverse (421258), we get a palindrome (8942498).

The spelling of 8521240 in words is "eight million, five hundred twenty-one thousand, two hundred forty".