25661621340323 has 2 divisors, whose sum is σ = 25661621340324. Its totient is φ = 25661621340322.

The previous prime is 25661621340281. The next prime is 25661621340389. The reversal of 25661621340323 is 32304312616652.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 25661621340323 - 2⁶ = 25661621340259 is a prime.

It is not a weakly prime, because it can be changed into another prime (25661621340623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12830810670161 + 12830810670162.

It is an arithmetic number, because the mean of its divisors is an integer number (12830810670162).

Almost surely, 2^{25661621340323} is an apocalyptic number.

25661621340323 is a deficient number, since it is larger than the sum of its proper divisors (1).

25661621340323 is an equidigital number, since it uses as much as digits as its factorization.

25661621340323 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 933120, while the sum is 44.

Adding to 25661621340323 its reverse (32304312616652), we get a palindrome (57965933956975).

The spelling of 25661621340323 in words is "twenty-five trillion, six hundred sixty-one billion, six hundred twenty-one million, three hundred forty thousand, three hundred twenty-three".