25819031221 has 2 divisors, whose sum is σ = 25819031222. Its totient is φ = 25819031220.

The previous prime is 25819031191. The next prime is 25819031233. The reversal of 25819031221 is 12213091852.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25174582225 + 644448996 = 158665^2 + 25386^2 .

It is a cyclic number.

It is not a de Polignac number, because 25819031221 - 2⁹ = 25819030709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25819031521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12909515610 + 12909515611.

It is an arithmetic number, because the mean of its divisors is an integer number (12909515611).

Almost surely, 2^25819031221 is an apocalyptic number.

It is an amenable number.

25819031221 is a deficient number, since it is larger than the sum of its proper divisors (1).

25819031221 is an equidigital number, since it uses as much as digits as its factorization.

25819031221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 34.

The spelling of 25819031221 in words is "twenty-five billion, eight hundred nineteen million, thirty-one thousand, two hundred twenty-one".