21206521025320 has 64 divisors (see below), whose sum is σ = 48026263703040. Its totient is φ = 8427369350400.

The previous prime is 21206521025299. The next prime is 21206521025351. The reversal of 21206521025320 is 2352012560212.

It is a super-2 number, since 2×21206521025320² (a number of 27 digits) contains 22 as substring.

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 15 ways as a sum of consecutive naturals, for example, 1958730 + ... + 6800710.

It is an arithmetic number, because the mean of its divisors is an integer number (750410370360).

Almost surely, 2^{21206521025320} is an apocalyptic number.

21206521025320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21206521025320 is an abundant number, since it is smaller than the sum of its proper divisors (26819742677720).

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

21206521025320 is a wasteful number, since it uses less digits than its factorization.

21206521025320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4842706 (or 4842702 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 31.

Adding to 21206521025320 its reverse (2352012560212), we get a palindrome (23558533585532).

The spelling of 21206521025320 in words is "twenty-one trillion, two hundred six billion, five hundred twenty-one million, twenty-five thousand, three hundred twenty".