21725240204717 has 4 divisors (see below), whose sum is σ = 24828845948256. Its totient is φ = 18621634461180.

The previous prime is 21725240204713. The next prime is 21725240204747. The reversal of 21725240204717 is 71740204252712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21725240204717 - 2² = 21725240204713 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21725240204713) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1551802871759 + ... + 1551802871772.

It is an arithmetic number, because the mean of its divisors is an integer number (6207211487064).

Almost surely, 2^{21725240204717} is an apocalyptic number.

It is an amenable number.

21725240204717 is a deficient number, since it is larger than the sum of its proper divisors (3103605743539).

21725240204717 is an equidigital number, since it uses as much as digits as its factorization.

21725240204717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3103605743538.

The product of its (nonzero) digits is 439040, while the sum is 44.

The spelling of 21725240204717 in words is "twenty-one trillion, seven hundred twenty-five billion, two hundred forty million, two hundred four thousand, seven hundred seventeen".