2500781 has 2 divisors, whose sum is σ = 2500782. Its totient is φ = 2500780.

The previous prime is 2500769. The next prime is 2500783. The reversal of 2500781 is 1870052.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2128681 + 372100 = 1459^2 + 610^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2500781 is a prime.

It is a super-2 number, since 2×2500781² = 12507811219922, which contains 22 as substring.

Together with 2500783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2500783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1250390 + 1250391.

It is an arithmetic number, because the mean of its divisors is an integer number (1250391).

2^2500781 is an apocalyptic number.

It is an amenable number.

2500781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2500781 is an equidigital number, since it uses as much as digits as its factorization.

2500781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 2500781 is about 1581.3857846838. The cubic root of 2500781 is about 135.7350124260.

The spelling of 2500781 in words is "two million, five hundred thousand, seven hundred eighty-one".