20521136064 has 224 divisors, whose sum is σ = 64601994240. Its totient is φ = 5666918400.

The previous prime is 20521136057. The next prime is 20521136081. The reversal of 20521136064 is 46063112502.

It is a super-2 number, since 2×20521136064² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2164294 + ... + 2173754.

It is an arithmetic number, because the mean of its divisors is an integer number (288401760).

Almost surely, 2^20521136064 is an apocalyptic number.

20521136064 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 20521136064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32300997120).

20521136064 is an abundant number, since it is smaller than the sum of its proper divisors (44080858176).

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

20521136064 is a wasteful number, since it uses less digits than its factorization.

20521136064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9579 (or 9569 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

Adding to 20521136064 its reverse (46063112502), we get a palindrome (66584248566).

The spelling of 20521136064 in words is "twenty billion, five hundred twenty-one million, one hundred thirty-six thousand, sixty-four".