2615581 has 2 divisors, whose sum is σ = 2615582. Its totient is φ = 2615580.

The previous prime is 2615551. The next prime is 2615593. The reversal of 2615581 is 1855162.

2615581 = T₁₃₁₉ + T₁₃₂₀ + T₁₃₂₁.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2295225 + 320356 = 1515^2 + 566^2 .

It is a cyclic number.

It is not a de Polignac number, because 2615581 - 2⁹ = 2615069 is a prime.

It is a super-2 number, since 2×2615581² = 13682527935122, which contains 22 as substring.

2615581 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2615531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1307790 + 1307791.

It is an arithmetic number, because the mean of its divisors is an integer number (1307791).

2^2615581 is an apocalyptic number.

2615581 is the 1321-st centered triangular number.

It is an amenable number.

2615581 is a deficient number, since it is larger than the sum of its proper divisors (1).

2615581 is an equidigital number, since it uses as much as digits as its factorization.

2615581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2400, while the sum is 28.

The square root of 2615581 is about 1617.2757958988. The cubic root of 2615581 is about 137.7810186591.

The spelling of 2615581 in words is "two million, six hundred fifteen thousand, five hundred eighty-one".