20641853856 has 288 divisors, whose sum is σ = 61506926208. Its totient is φ = 6024130560.

The previous prime is 20641853851. The next prime is 20641853887. The reversal of 20641853856 is 65835814602.

It is a happy number.

It is a super-2 number, since 2×20641853856² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (20641853851) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 74519190 + ... + 74519466.

It is an arithmetic number, because the mean of its divisors is an integer number (213565716).

Almost surely, 2^20641853856 is an apocalyptic number.

20641853856 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 20641853856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30753463104).

20641853856 is an abundant number, since it is smaller than the sum of its proper divisors (40865072352).

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

20641853856 is a wasteful number, since it uses less digits than its factorization.

20641853856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 432 (or 395 counting only the distinct ones).

The product of its (nonzero) digits is 1382400, while the sum is 48.

The spelling of 20641853856 in words is "twenty billion, six hundred forty-one million, eight hundred fifty-three thousand, eight hundred fifty-six".