20687955456 has 160 divisors (see below), whose sum is σ = 63188598528. Its totient is φ = 5891973120.

The previous prime is 20687955451. The next prime is 20687955479. The reversal of 20687955456 is 65455978602.

It is a junction number, because it is equal to n+sod(n) for n = 20687955396 and 20687955405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20687955451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3556006 + ... + 3561818.

Almost surely, 2^20687955456 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 20687955456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31594299264).

20687955456 is an abundant number, since it is smaller than the sum of its proper divisors (42500643072).

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

20687955456 is an equidigital number, since it uses as much as digits as its factorization.

20687955456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6172 (or 6156 counting only the distinct ones).

The product of its (nonzero) digits is 18144000, while the sum is 57.

The spelling of 20687955456 in words is "twenty billion, six hundred eighty-seven million, nine hundred fifty-five thousand, four hundred fifty-six".