25644545021 has 2 divisors, whose sum is σ = 25644545022. Its totient is φ = 25644545020.

The previous prime is 25644544993. The next prime is 25644545023. The reversal of 25644545021 is 12054544652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22865673796 + 2778871225 = 151214^2 + 52715^2 .

It is a cyclic number.

It is not a de Polignac number, because 25644545021 - 2⁶ = 25644544957 is a prime.

Together with 25644545023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25644545023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12822272510 + 12822272511.

It is an arithmetic number, because the mean of its divisors is an integer number (12822272511).

Almost surely, 2^25644545021 is an apocalyptic number.

It is an amenable number.

25644545021 is a deficient number, since it is larger than the sum of its proper divisors (1).

25644545021 is an equidigital number, since it uses as much as digits as its factorization.

25644545021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192000, while the sum is 38.

The spelling of 25644545021 in words is "twenty-five billion, six hundred forty-four million, five hundred forty-five thousand, twenty-one".