2545681 has 2 divisors, whose sum is σ = 2545682. Its totient is φ = 2545680.

The previous prime is 2545679. The next prime is 2545687. The reversal of 2545681 is 1865452.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2531281 + 14400 = 1591^2 + 120^2 .

It is a cyclic number.

It is not a de Polignac number, because 2545681 - 2¹ = 2545679 is a prime.

It is a super-2 number, since 2×2545681² = 12960983507522, which contains 22 as substring.

Together with 2545679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (2545687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1272840 + 1272841.

It is an arithmetic number, because the mean of its divisors is an integer number (1272841).

2^2545681 is an apocalyptic number.

It is an amenable number.

2545681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2545681 is an equidigital number, since it uses as much as digits as its factorization.

2545681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9600, while the sum is 31.

The square root of 2545681 is about 1595.5190378056. The cubic root of 2545681 is about 136.5425451156.

The spelling of 2545681 in words is "two million, five hundred forty-five thousand, six hundred eighty-one".