25784021 has 2 divisors, whose sum is σ = 25784022. Its totient is φ = 25784020.

The previous prime is 25783999. The next prime is 25784041. The reversal of 25784021 is 12048752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17724100 + 8059921 = 4210^2 + 2839^2 .

It is a cyclic number.

It is not a de Polignac number, because 25784021 - 2¹⁰ = 25782997 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25784041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12892010 + 12892011.

It is an arithmetic number, because the mean of its divisors is an integer number (12892011).

Almost surely, 2^25784021 is an apocalyptic number.

It is an amenable number.

25784021 is a deficient number, since it is larger than the sum of its proper divisors (1).

25784021 is an equidigital number, since it uses as much as digits as its factorization.

25784021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 25784021 is about 5077.7968647830. The cubic root of 25784021 is about 295.4270211433.

The spelling of 25784021 in words is "twenty-five million, seven hundred eighty-four thousand, twenty-one".