20987667558 has 216 divisors, whose sum is σ = 56991228840. Its totient is φ = 5559840000.

The previous prime is 20987667557. The next prime is 20987667559. The reversal of 20987667558 is 85576678902.

20987667558 is a `hidden beast` number, since 2 + 0 + 9 + 8 + 76 + 6 + 7 + 558 = 666.

It is an interprime number because it is at equal distance from previous prime (20987667557) and next prime (20987667559).

It is a junction number, because it is equal to n+sod(n) for n = 20987667495 and 20987667504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20987667553) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 6992058 + ... + 6995058.

Almost surely, 2^20987667558 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20987667558, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28495614420).

20987667558 is an abundant number, since it is smaller than the sum of its proper divisors (36003561282).

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

20987667558 is a wasteful number, since it uses less digits than its factorization.

20987667558 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3076 (or 3049 counting only the distinct ones).

The product of its (nonzero) digits is 50803200, while the sum is 63.

The spelling of 20987667558 in words is "twenty billion, nine hundred eighty-seven million, six hundred sixty-seven thousand, five hundred fifty-eight".