21263210642421 has 96 divisors (see below), whose sum is σ = 36215107568640. Its totient is φ = 11877825753600.

The previous prime is 21263210642417. The next prime is 21263210642441. The reversal of 21263210642421 is 12424601236212.

21263210642421 is a `hidden beast` number, since 2 + 1 + 2 + 6 + 3 + 2 + 1 + 0 + 642 + 4 + 2 + 1 = 666.

It is not a de Polignac number, because 21263210642421 - 2² = 21263210642417 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21263210642441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 25708006 + ... + 26522216.

It is an arithmetic number, because the mean of its divisors is an integer number (377240703840).

Almost surely, 2^{21263210642421} is an apocalyptic number.

It is an amenable number.

21263210642421 is a deficient number, since it is larger than the sum of its proper divisors (14951896926219).

21263210642421 is a wasteful number, since it uses less digits than its factorization.

21263210642421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 814567 (or 814564 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

Adding to 21263210642421 its reverse (12424601236212), we get a palindrome (33687811878633).

The spelling of 21263210642421 in words is "twenty-one trillion, two hundred sixty-three billion, two hundred ten million, six hundred forty-two thousand, four hundred twenty-one".