21695312077825 has 6 divisors (see below), whose sum is σ = 26902186976534. Its totient is φ = 17356249662240.

The previous prime is 21695312077763. The next prime is 21695312077861. The reversal of 21695312077825 is 52877021359612.

It can be written as a sum of positive squares in 3 ways, for example, as 292327292929 + 21402984784896 = 540673^2 + 4626336^2 .

It is not a de Polignac number, because 21695312077825 - 2²⁹ = 21694775206913 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21695312077825.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 433906241532 + ... + 433906241581.

Almost surely, 2^{21695312077825} is an apocalyptic number.

21695312077825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21695312077825 is a deficient number, since it is larger than the sum of its proper divisors (5206874898709).

21695312077825 is an equidigital number, since it uses as much as digits as its factorization.

21695312077825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 867812483123 (or 867812483118 counting only the distinct ones).

The product of its (nonzero) digits is 12700800, while the sum is 58.

The spelling of 21695312077825 in words is "twenty-one trillion, six hundred ninety-five billion, three hundred twelve million, seventy-seven thousand, eight hundred twenty-five".