21221032321220 has 24 divisors (see below), whose sum is σ = 44589764827608. Its totient is φ = 8483537318400.

The previous prime is 21221032321217. The next prime is 21221032321231. The reversal of 21221032321220 is 2212323012212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1121663155396 + 20099369165824 = 1059086^2 + 4483232^2 .

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, 304689941 + ... + 304759580.

It is an arithmetic number, because the mean of its divisors is an integer number (1857906867817).

Almost surely, 2^{21221032321220} is an apocalyptic number.

21221032321220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221032321220 is an abundant number, since it is smaller than the sum of its proper divisors (23368732506388).

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

21221032321220 is a wasteful number, since it uses less digits than its factorization.

21221032321220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 609451271 (or 609451269 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

Adding to 21221032321220 its reverse (2212323012212), we get a palindrome (23433355333432).

The spelling of 21221032321220 in words is "twenty-one trillion, two hundred twenty-one billion, thirty-two million, three hundred twenty-one thousand, two hundred twenty".