2561787 has 10 divisors (see below), whose sum is σ = 3826988. Its totient is φ = 1707804.

The previous prime is 2561771. The next prime is 2561807. The reversal of 2561787 is 7871652.

It is not a de Polignac number, because 2561787 - 2⁴ = 2561771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2561737) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 15733 + ... + 15894.

2^2561787 is an apocalyptic number.

2561787 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

2561787 is a deficient number, since it is larger than the sum of its proper divisors (1265201).

2561787 is an equidigital number, since it uses as much as digits as its factorization.

2561787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31639 (or 31630 counting only the distinct ones).

The product of its digits is 23520, while the sum is 36.

The square root of 2561787 is about 1600.5583400801. The cubic root of 2561787 is about 136.8298988204.

The spelling of 2561787 in words is "two million, five hundred sixty-one thousand, seven hundred eighty-seven".