25540421 has 2 divisors, whose sum is σ = 25540422. Its totient is φ = 25540420.

The previous prime is 25540399. The next prime is 25540447. The reversal of 25540421 is 12404552.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18576100 + 6964321 = 4310^2 + 2639^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25540421 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 (25540721) 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, 12770210 + 12770211.

It is an arithmetic number, because the mean of its divisors is an integer number (12770211).

Almost surely, 2^25540421 is an apocalyptic number.

It is an amenable number.

25540421 is a deficient number, since it is larger than the sum of its proper divisors (1).

25540421 is an equidigital number, since it uses as much as digits as its factorization.

25540421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1600, while the sum is 23.

The square root of 25540421 is about 5053.7531597814. The cubic root of 25540421 is about 294.4937059254.

Adding to 25540421 its reverse (12404552), we get a palindrome (37944973).

The spelling of 25540421 in words is "twenty-five million, five hundred forty thousand, four hundred twenty-one".