25660206221 has 8 divisors (see below), whose sum is σ = 27636769944. Its totient is φ = 23684028480.

The previous prime is 25660206203. The next prime is 25660206239. The reversal of 25660206221 is 12260206652.

It is an interprime number because it is at equal distance from previous prime (25660206203) and next prime (25660206239).

It can be written as a sum of positive squares in 4 ways, for example, as 1860973321 + 23799232900 = 43139^2 + 154270^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 25660206221 - 2²⁶ = 25593097357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25660206721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49811 + ... + 231951.

It is an arithmetic number, because the mean of its divisors is an integer number (3454596243).

Almost surely, 2^25660206221 is an apocalyptic number.

It is an amenable number.

25660206221 is a deficient number, since it is larger than the sum of its proper divisors (1976563723).

25660206221 is a wasteful number, since it uses less digits than its factorization.

25660206221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192991.

The product of its (nonzero) digits is 17280, while the sum is 32.

The spelling of 25660206221 in words is "twenty-five billion, six hundred sixty million, two hundred six thousand, two hundred twenty-one".