20715520565551 has 4 divisors (see below), whose sum is σ = 23674880646352. Its totient is φ = 17756160484752.

The previous prime is 20715520565449. The next prime is 20715520565557. The reversal of 20715520565551 is 15556502551702.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20715520565551 - 2¹¹ = 20715520563503 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20715520565495 and 20715520565504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20715520565557) 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, 1479680040390 + ... + 1479680040403.

It is an arithmetic number, because the mean of its divisors is an integer number (5918720161588).

Almost surely, 2^{20715520565551} is an apocalyptic number.

20715520565551 is a deficient number, since it is larger than the sum of its proper divisors (2959360080801).

20715520565551 is an equidigital number, since it uses as much as digits as its factorization.

20715520565551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2959360080800.

The product of its (nonzero) digits is 2625000, while the sum is 49.

The spelling of 20715520565551 in words is "twenty trillion, seven hundred fifteen billion, five hundred twenty million, five hundred sixty-five thousand, five hundred fifty-one".