20520236615656 has 8 divisors (see below), whose sum is σ = 38475443654370. Its totient is φ = 10260118307824.

The previous prime is 20520236615597. The next prime is 20520236615657. The reversal of 20520236615656 is 65651663202502.

It can be written as a sum of positive squares in only one way, i.e., 20514250498756 + 5986116900 = 4529266^2 + 77370^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×20520236615656² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20520236615657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1282514788471 + ... + 1282514788486.

Almost surely, 2^{20520236615656} is an apocalyptic number.

It is an amenable number.

20520236615656 is a deficient number, since it is larger than the sum of its proper divisors (17955207038714).

20520236615656 is a wasteful number, since it uses less digits than its factorization.

20520236615656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2565029576963 (or 2565029576959 counting only the distinct ones).

The product of its (nonzero) digits is 3888000, while the sum is 49.

The spelling of 20520236615656 in words is "twenty trillion, five hundred twenty billion, two hundred thirty-six million, six hundred fifteen thousand, six hundred fifty-six".