25643621 has 2 divisors, whose sum is σ = 25643622. Its totient is φ = 25643620.

The previous prime is 25643593. The next prime is 25643663. The reversal of 25643621 is 12634652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16120225 + 9523396 = 4015^2 + 3086^2 .

It is a cyclic number.

It is not a de Polignac number, because 25643621 - 2⁶ = 25643557 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25643671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12821810 + 12821811.

It is an arithmetic number, because the mean of its divisors is an integer number (12821811).

Almost surely, 2^25643621 is an apocalyptic number.

It is an amenable number.

25643621 is a deficient number, since it is larger than the sum of its proper divisors (1).

25643621 is an equidigital number, since it uses as much as digits as its factorization.

25643621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 29.

The square root of 25643621 is about 5063.9531000988. The cubic root of 25643621 is about 294.8898219214.

The spelling of 25643621 in words is "twenty-five million, six hundred forty-three thousand, six hundred twenty-one".