25567721 has 2 divisors, whose sum is σ = 25567722. Its totient is φ = 25567720.

The previous prime is 25567699. The next prime is 25567741. The reversal of 25567721 is 12776552.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18619225 + 6948496 = 4315^2 + 2636^2 .

It is a cyclic number.

It is not a de Polignac number, because 25567721 - 2⁶ = 25567657 is a prime.

It is not a weakly prime, because it can be changed into another prime (25567741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12783860 + 12783861.

It is an arithmetic number, because the mean of its divisors is an integer number (12783861).

Almost surely, 2^25567721 is an apocalyptic number.

It is an amenable number.

25567721 is a deficient number, since it is larger than the sum of its proper divisors (1).

25567721 is an equidigital number, since it uses as much as digits as its factorization.

25567721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 29400, while the sum is 35.

The square root of 25567721 is about 5056.4534013476. The cubic root of 25567721 is about 294.5985960699.

It can be divided in two parts, 255 and 67721, that added together give a palindrome (67976).

The spelling of 25567721 in words is "twenty-five million, five hundred sixty-seven thousand, seven hundred twenty-one".