8540721 has 24 divisors (see below), whose sum is σ = 14624064. Its totient is φ = 4879440.

The previous prime is 8540713. The next prime is 8540723. The reversal of 8540721 is 1270458.

It is not a de Polignac number, because 8540721 - 2³ = 8540713 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (8540723) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 810 + ... + 4211.

It is an arithmetic number, because the mean of its divisors is an integer number (609336).

Almost surely, 2^8540721 is an apocalyptic number.

8540721 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

8540721 is a deficient number, since it is larger than the sum of its proper divisors (6083343).

8540721 is an equidigital number, since it uses as much as digits as its factorization.

8540721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5043 (or 5031 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 8540721 is about 2922.4511971973. The cubic root of 8540721 is about 204.4081361978.

It can be divided in two parts, 8540 and 721, that added together give a cube (9261 = 21³).

The spelling of 8540721 in words is "eight million, five hundred forty thousand, seven hundred twenty-one".