2564003661 has 4 divisors (see below), whose sum is σ = 3418671552. Its totient is φ = 1709335772.

The previous prime is 2564003653. The next prime is 2564003669. The reversal of 2564003661 is 1663004652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (2564003653) and next prime (2564003669).

It is a cyclic number.

It is not a de Polignac number, because 2564003661 - 2³ = 2564003653 is a prime.

It is a super-2 number, since 2×2564003661² = 13148229547242805842, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2564003669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 427333941 + ... + 427333946.

It is an arithmetic number, because the mean of its divisors is an integer number (854667888).

Almost surely, 2^2564003661 is an apocalyptic number.

It is an amenable number.

2564003661 is a deficient number, since it is larger than the sum of its proper divisors (854667891).

2564003661 is an equidigital number, since it uses as much as digits as its factorization.

2564003661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 854667890.

The product of its (nonzero) digits is 25920, while the sum is 33.

The square root of 2564003661 is about 50635.9917548773. The cubic root of 2564003661 is about 1368.6935279801.

Subtracting from 2564003661 its reverse (1663004652), we obtain a palindrome (900999009).

The spelling of 2564003661 in words is "two billion, five hundred sixty-four million, three thousand, six hundred sixty-one".