25620821 has 2 divisors, whose sum is σ = 25620822. Its totient is φ = 25620820.

The previous prime is 25620817. The next prime is 25620823. The reversal of 25620821 is 12802652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25150225 + 470596 = 5015^2 + 686^2 .

It is a cyclic number.

It is not a de Polignac number, because 25620821 - 2² = 25620817 is a prime.

Together with 25620823, 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 (25620823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12810410 + 12810411.

It is an arithmetic number, because the mean of its divisors is an integer number (12810411).

Almost surely, 2^25620821 is an apocalyptic number.

It is an amenable number.

25620821 is a deficient number, since it is larger than the sum of its proper divisors (1).

25620821 is an equidigital number, since it uses as much as digits as its factorization.

25620821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 25620821 is about 5061.7013938003. The cubic root of 25620821 is about 294.8023995099.

The spelling of 25620821 in words is "twenty-five million, six hundred twenty thousand, eight hundred twenty-one".