20021156064 has 576 divisors, whose sum is σ = 76200284160. Its totient is φ = 4837294080.

The previous prime is 20021156047. The next prime is 20021156069. The reversal of 20021156064 is 46065112002.

20021156064 is a `hidden beast` number, since 20 + 0 + 21 + 1 + 560 + 64 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021156069) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 15435864 + ... + 15437160.

It is an arithmetic number, because the mean of its divisors is an integer number (132292160).

Almost surely, 2^20021156064 is an apocalyptic number.

20021156064 is a gapful number since it is divisible by the number (24) 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 20021156064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38100142080).

20021156064 is an abundant number, since it is smaller than the sum of its proper divisors (56179128096).

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

20021156064 is a wasteful number, since it uses less digits than its factorization.

20021156064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1383 (or 1372 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

Adding to 20021156064 its reverse (46065112002), we get a palindrome (66086268066).

The spelling of 20021156064 in words is "twenty billion, twenty-one million, one hundred fifty-six thousand, sixty-four".