21156003623220 has 24 divisors (see below), whose sum is σ = 59236810145184. Its totient is φ = 5641600966176.

The previous prime is 21156003623213. The next prime is 21156003623267. The reversal of 21156003623220 is 2232630065112.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 176300030134 + ... + 176300030253.

It is an arithmetic number, because the mean of its divisors is an integer number (2468200422716).

Almost surely, 2^{21156003623220} is an apocalyptic number.

21156003623220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21156003623220 is an abundant number, since it is smaller than the sum of its proper divisors (38080806521964).

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

21156003623220 is a wasteful number, since it uses less digits than its factorization.

21156003623220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352600060399 (or 352600060397 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 33.

Adding to 21156003623220 its reverse (2232630065112), we get a palindrome (23388633688332).

The spelling of 21156003623220 in words is "twenty-one trillion, one hundred fifty-six billion, three million, six hundred twenty-three thousand, two hundred twenty".