25721239 has 2 divisors, whose sum is σ = 25721240. Its totient is φ = 25721238.

The previous prime is 25721203. The next prime is 25721251. The reversal of 25721239 is 93212752.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 25721239 - 2⁹ = 25720727 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 25721239.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25721299) 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, 12860619 + 12860620.

It is an arithmetic number, because the mean of its divisors is an integer number (12860620).

Almost surely, 2^25721239 is an apocalyptic number.

25721239 is a deficient number, since it is larger than the sum of its proper divisors (1).

25721239 is an equidigital number, since it uses as much as digits as its factorization.

25721239 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7560, while the sum is 31.

The square root of 25721239 is about 5071.6110852470. The cubic root of 25721239 is about 295.1870459855.

The spelling of 25721239 in words is "twenty-five million, seven hundred twenty-one thousand, two hundred thirty-nine".