2564521 has 2 divisors, whose sum is σ = 2564522. Its totient is φ = 2564520.

The previous prime is 2564519. The next prime is 2564539. The reversal of 2564521 is 1254652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2496400 + 68121 = 1580^2 + 261^2 .

It is a cyclic number.

It is not a de Polignac number, because 2564521 - 2¹ = 2564519 is a prime.

Together with 2564519, it forms a pair of twin primes.

2564521 is a lucky number.

It is equal to p₁₈₇₄₅₀ and since 2564521 and 187450 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2564561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1282260 + 1282261.

It is an arithmetic number, because the mean of its divisors is an integer number (1282261).

2^2564521 is an apocalyptic number.

It is an amenable number.

2564521 is a deficient number, since it is larger than the sum of its proper divisors (1).

2564521 is an equidigital number, since it uses as much as digits as its factorization.

2564521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2400, while the sum is 25.

The square root of 2564521 is about 1601.4121892879. The cubic root of 2564521 is about 136.8785575551.

It can be divided in two parts, 25 and 64521, that added together give a palindrome (64546).

The spelling of 2564521 in words is "two million, five hundred sixty-four thousand, five hundred twenty-one".