20856890520 has 432 divisors, whose sum is σ = 74365134480. Its totient is φ = 5068604160.

The previous prime is 20856890513. The next prime is 20856890533. The reversal of 20856890520 is 2509865802.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 124891477 + ... + 124891643.

It is an arithmetic number, because the mean of its divisors is an integer number (172141515).

Almost surely, 2^20856890520 is an apocalyptic number.

20856890520 is a gapful number since it is divisible by the number (20) 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 20856890520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37182567240).

20856890520 is an abundant number, since it is smaller than the sum of its proper divisors (53508243960).

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

20856890520 is a wasteful number, since it uses less digits than its factorization.

20856890520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284 (or 227 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The spelling of 20856890520 in words is "twenty billion, eight hundred fifty-six million, eight hundred ninety thousand, five hundred twenty".