8720581 has 2 divisors, whose sum is σ = 8720582. Its totient is φ = 8720580.

The previous prime is 8720557. The next prime is 8720597. The reversal of 8720581 is 1850278.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8608356 + 112225 = 2934^2 + 335^2 .

It is a cyclic number.

It is not a de Polignac number, because 8720581 - 2²³ = 331973 is a prime.

It is a super-2 number, since 2×8720581² = 152097065955122, which contains 22 as substring.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8720531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4360290 + 4360291.

It is an arithmetic number, because the mean of its divisors is an integer number (4360291).

Almost surely, 2^8720581 is an apocalyptic number.

It is an amenable number.

8720581 is a deficient number, since it is larger than the sum of its proper divisors (1).

8720581 is an equidigital number, since it uses as much as digits as its factorization.

8720581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4480, while the sum is 31.

The square root of 8720581 is about 2953.0629861214. The cubic root of 8720581 is about 205.8330645566.

The spelling of 8720581 in words is "eight million, seven hundred twenty thousand, five hundred eighty-one".