21155324222400 has 168 divisors, whose sum is σ = 70716661527024. Its totient is φ = 5534977843200.

The previous prime is 21155324222393. The next prime is 21155324222401. The reversal of 21155324222400 is 422242355112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155324222401) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41324461 + ... + 41833260.

Almost surely, 2^{21155324222400} is an apocalyptic number.

21155324222400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21155324222400 is an abundant number, since it is smaller than the sum of its proper divisors (49561337304624).

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

21155324222400 is a wasteful number, since it uses less digits than its factorization.

21155324222400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83157799 (or 83157784 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 33.

Adding to 21155324222400 its reverse (422242355112), we get a palindrome (21577566577512).

The spelling of 21155324222400 in words is "twenty-one trillion, one hundred fifty-five billion, three hundred twenty-four million, two hundred twenty-two thousand, four hundred".