2604001861 has 4 divisors (see below), whose sum is σ = 2604110112. Its totient is φ = 2603893612.

The previous prime is 2604001849. The next prime is 2604001903. The reversal of 2604001861 is 1681004062.

2604001861 is a nontrivial binomial coefficient, being equal to C(72167, 2).

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, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 2604001861 - 2⁹ = 2604001349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2604001801) 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, 1 + ... + 72166.

It is an arithmetic number, because the mean of its divisors is an integer number (651027528).

Almost surely, 2^2604001861 is an apocalyptic number.

2604001861 is the 72166-th triangular number.

2604001861 is the 24056-th centered nonagonal number.

It is an amenable number.

2604001861 is a deficient number, since it is larger than the sum of its proper divisors (108251).

2604001861 is an equidigital number, since it uses as much as digits as its factorization.

2604001861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108250.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 2604001861 is about 51029.4215232742. The cubic root of 2604001861 is about 1375.7739970234.

The spelling of 2604001861 in words is "two billion, six hundred four million, one thousand, eight hundred sixty-one".