20751606566557 has 4 divisors (see below), whose sum is σ = 20849955413056. Its totient is φ = 20653257720060.

The previous prime is 20751606566527. The next prime is 20751606566597. The reversal of 20751606566557 is 75566560615702.

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 20751606566557 - 2³¹ = 20749459082909 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20751606566495 and 20751606566504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20751606566527) 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, 49174422933 + ... + 49174423354.

It is an arithmetic number, because the mean of its divisors is an integer number (5212488853264).

Almost surely, 2^{20751606566557} is an apocalyptic number.

It is an amenable number.

20751606566557 is a deficient number, since it is larger than the sum of its proper divisors (98348846499).

20751606566557 is an equidigital number, since it uses as much as digits as its factorization.

20751606566557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98348846498.

The product of its (nonzero) digits is 79380000, while the sum is 61.

The spelling of 20751606566557 in words is "twenty trillion, seven hundred fifty-one billion, six hundred six million, five hundred sixty-six thousand, five hundred fifty-seven".