25145821 has 2 divisors, whose sum is σ = 25145822. Its totient is φ = 25145820.

The previous prime is 25145807. The next prime is 25145849. The reversal of 25145821 is 12854152.

It is an a-pointer prime, because the next prime (25145849) can be obtained adding 25145821 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25140196 + 5625 = 5014^2 + 75^2 .

It is a cyclic number.

It is not a de Polignac number, because 25145821 - 2¹⁷ = 25014749 is a prime.

It is a Chen prime.

It is equal to p_1574506 and since 25145821 and 1574506 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 25145821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25145881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12572910 + 12572911.

It is an arithmetic number, because the mean of its divisors is an integer number (12572911).

Almost surely, 2^25145821 is an apocalyptic number.

It is an amenable number.

25145821 is a deficient number, since it is larger than the sum of its proper divisors (1).

25145821 is an equidigital number, since it uses as much as digits as its factorization.

25145821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3200, while the sum is 28.

The square root of 25145821 is about 5014.5608980249. The cubic root of 25145821 is about 292.9691829656.

Adding to 25145821 its reverse (12854152), we get a palindrome (37999973).

The spelling of 25145821 in words is "twenty-five million, one hundred forty-five thousand, eight hundred twenty-one".