20555991456 has 384 divisors, whose sum is σ = 76716896256. Its totient is φ = 4638228480.

The previous prime is 20555991427. The next prime is 20555991493. The reversal of 20555991456 is 65419955502.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a junction number, because it is equal to n+sod(n) for n = 20555991399 and 20555991408.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1627341 + ... + 1639923.

It is an arithmetic number, because the mean of its divisors is an integer number (199783584).

Almost surely, 2^20555991456 is an apocalyptic number.

20555991456 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20555991456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38358448128).

20555991456 is an abundant number, since it is smaller than the sum of its proper divisors (56160904800).

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

20555991456 is a wasteful number, since it uses less digits than its factorization.

20555991456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12644 (or 12636 counting only the distinct ones).

The product of its (nonzero) digits is 2430000, while the sum is 51.

The spelling of 20555991456 in words is "twenty billion, five hundred fifty-five million, nine hundred ninety-one thousand, four hundred fifty-six".