25278821 has 2 divisors, whose sum is σ = 25278822. Its totient is φ = 25278820.

The previous prime is 25278811. The next prime is 25278833. The reversal of 25278821 is 12887252.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17522596 + 7756225 = 4186^2 + 2785^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25278821 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25278811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12639410 + 12639411.

It is an arithmetic number, because the mean of its divisors is an integer number (12639411).

Almost surely, 2^25278821 is an apocalyptic number.

It is an amenable number.

25278821 is a deficient number, since it is larger than the sum of its proper divisors (1).

25278821 is an equidigital number, since it uses as much as digits as its factorization.

25278821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17920, while the sum is 35.

The square root of 25278821 is about 5027.8047893688. The cubic root of 25278821 is about 293.4847942267.

The spelling of 25278821 in words is "twenty-five million, two hundred seventy-eight thousand, eight hundred twenty-one".