21400520064636 has 48 divisors (see below), whose sum is σ = 50255587504640. Its totient is φ = 7087771667520.

The previous prime is 21400520064617. The next prime is 21400520064653. The reversal of 21400520064636 is 63646002500412.

It is a junction number, because it is equal to n+sod(n) for n = 21400520064594 and 21400520064603.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6657280 + ... + 9333831.

Almost surely, 2^{21400520064636} is an apocalyptic number.

It is an amenable number.

21400520064636 is an abundant number, since it is smaller than the sum of its proper divisors (28855067440004).

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

21400520064636 is a wasteful number, since it uses less digits than its factorization.

21400520064636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15991834 (or 15991832 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 39.

The spelling of 21400520064636 in words is "twenty-one trillion, four hundred billion, five hundred twenty million, sixty-four thousand, six hundred thirty-six".