21224156556400 has 60 divisors (see below), whose sum is σ = 58275469866832. Its totient is φ = 7276853675520.

The previous prime is 21224156556389. The next prime is 21224156556403. The reversal of 21224156556400 is 465565142212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21224156556403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3790025157 + ... + 3790030756.

Almost surely, 2^{21224156556400} is an apocalyptic number.

21224156556400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21224156556400 is an abundant number, since it is smaller than the sum of its proper divisors (37051313310432).

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

21224156556400 is a wasteful number, since it uses less digits than its factorization.

21224156556400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7580055938 (or 7580055927 counting only the distinct ones).

The product of its (nonzero) digits is 576000, while the sum is 43.

The spelling of 21224156556400 in words is "twenty-one trillion, two hundred twenty-four billion, one hundred fifty-six million, five hundred fifty-six thousand, four hundred".