20551004656 has 160 divisors (see below), whose sum is σ = 52846617600. Its totient is φ = 7513896960.

The previous prime is 20551004647. The next prime is 20551004681. The reversal of 20551004656 is 65640015502.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1125165 + ... + 1143283.

It is an arithmetic number, because the mean of its divisors is an integer number (330291360).

Almost surely, 2^20551004656 is an apocalyptic number.

20551004656 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 20551004656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26423308800).

20551004656 is an abundant number, since it is smaller than the sum of its proper divisors (32295612944).

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

20551004656 is a wasteful number, since it uses less digits than its factorization.

20551004656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18207 (or 18201 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 34.

The spelling of 20551004656 in words is "twenty billion, five hundred fifty-one million, four thousand, six hundred fifty-six".