20969655238656 has 180 divisors, whose sum is σ = 62649873811602. Its totient is φ = 6989881540608.

The previous prime is 20969655238601. The next prime is 20969655238663. The reversal of 20969655238656 is 65683255696902.

20969655238656 is a `hidden beast` number, since 2 + 0 + 9 + 6 + 9 + 6 + 552 + 3 + 8 + 65 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 11706251673600 + 9263403565056 = 3421440^2 + 3043584^2 .

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 9629266 + ... + 11604398.

Almost surely, 2^{20969655238656} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20969655238656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31324936905801).

20969655238656 is an abundant number, since it is smaller than the sum of its proper divisors (41680218572946).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20969655238656 is an frugal number, since it uses more digits than its factorization.

20969655238656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1975179 (or 1975138 counting only the distinct ones).

The product of its (nonzero) digits is 1259712000, while the sum is 72.

The spelling of 20969655238656 in words is "twenty trillion, nine hundred sixty-nine billion, six hundred fifty-five million, two hundred thirty-eight thousand, six hundred fifty-six".