20641256860225 has 9 divisors (see below), whose sum is σ = 25595186674953. Its totient is φ = 16512987315120.

The previous prime is 20641256860181. The next prime is 20641256860261. The reversal of 20641256860225 is 52206865214602.

The square root of 20641256860225 is 4543265.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 10460715895809 + 10180540964416 = 3234303^2 + 3190696^2 .

It is a de Polignac number, because none of the positive numbers 2^k-20641256860225 is a prime.

It is a super-3 number, since 3×20641256860225³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 22261999 + ... + 23170651.

Almost surely, 2^{20641256860225} is an apocalyptic number.

20641256860225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20641256860225 is the 4543265-th square number.

20641256860225 is the 2271633-rd centered octagonal number.

It is an amenable number.

20641256860225 is a deficient number, since it is larger than the sum of its proper divisors (4953929814728).

20641256860225 is an frugal number, since it uses more digits than its factorization.

20641256860225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1817316 (or 908658 counting only the distinct ones).

The product of its (nonzero) digits is 2764800, while the sum is 49.

The spelling of 20641256860225 in words is "twenty trillion, six hundred forty-one billion, two hundred fifty-six million, eight hundred sixty thousand, two hundred twenty-five".