20688935696640 has 216 divisors, whose sum is σ = 71995335604920. Its totient is φ = 5485158531072.

The previous prime is 20688935696579. The next prime is 20688935696641. The reversal of 20688935696640 is 4669653988602.

20688935696640 is a `hidden beast` number, since 206 + 8 + 8 + 9 + 356 + 9 + 6 + 64 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2353548720384 + 18335386976256 = 1534128^2 + 4281984^2 .

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

It is not an unprimeable number, because it can be changed into a prime (20688935696641) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3197545 + ... + 7183464.

Almost surely, 2^{20688935696640} is an apocalyptic number.

20688935696640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20688935696640 is an abundant number, since it is smaller than the sum of its proper divisors (51306399908280).

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

20688935696640 is a wasteful number, since it uses less digits than its factorization.

20688935696640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10381209 (or 10381192 counting only the distinct ones).

The product of its (nonzero) digits is 806215680, while the sum is 72.

The spelling of 20688935696640 in words is "twenty trillion, six hundred eighty-eight billion, nine hundred thirty-five million, six hundred ninety-six thousand, six hundred forty".