20656525671557 has 4 divisors (see below), whose sum is σ = 20714064740640. Its totient is φ = 20598986602476.

The previous prime is 20656525671547. The next prime is 20656525671631. The reversal of 20656525671557 is 75517652565602.

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 20656525671557 - 2¹⁴ = 20656525655173 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 20656525671557.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20656525671547) 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, 28769534003 + ... + 28769534720.

It is an arithmetic number, because the mean of its divisors is an integer number (5178516185160).

Almost surely, 2^{20656525671557} is an apocalyptic number.

It is an amenable number.

20656525671557 is a deficient number, since it is larger than the sum of its proper divisors (57539069083).

20656525671557 is an equidigital number, since it uses as much as digits as its factorization.

20656525671557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57539069082.

The product of its (nonzero) digits is 132300000, while the sum is 62.

The spelling of 20656525671557 in words is "twenty trillion, six hundred fifty-six billion, five hundred twenty-five million, six hundred seventy-one thousand, five hundred fifty-seven".